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96-583: C++ ( / ˈ s iː p l ʌ s p l ʌ s / , pronounced " C plus plus " and sometimes abbreviated as CPP ) is a high-level , general-purpose programming language created by Danish computer scientist Bjarne Stroustrup . First released in 1985 as an extension of the C programming language , it has since expanded significantly over time; as of 1997, C++ has object-oriented , generic , and functional features, in addition to facilities for low-level memory manipulation for systems like microcomputers or to make operating systems like Linux or Windows . It

192-521: A base class exists in the inheritance graph, avoiding some of the ambiguity problems of multiple inheritance. Multiple inheritance is a C++ feature allowing a class to be derived from more than one base class; this allows for more elaborate inheritance relationships. For example, a "Flying Cat" class can inherit from both "Cat" and "Flying Mammal". Some other languages, such as C# or Java , accomplish something similar (although more limited) by allowing inheritance of multiple interfaces while restricting

288-446: A constructor or initializer this is used to define the initial state of the object. Local variables are destroyed when the local block or function that they are declared in is closed. C++ destructors for local variables are called at the end of the object lifetime, allowing a discipline for automatic resource management termed RAII , which is widely used in C++. Member variables are created when

384-402: A cost. Template use may increase object code size, because each template instantiation produces a copy of the template code: one for each set of template arguments, however, this is the same or smaller amount of code that would be generated if the code were written by hand. This is in contrast to run-time generics seen in other languages (e.g., Java ) where at compile-time the type is erased and

480-495: A direct mapping of hardware features provided primarily by the C subset, and zero-overhead abstractions based on those mappings. Stroustrup describes C++ as "a light-weight abstraction programming language [designed] for building and using efficient and elegant abstractions"; and "offering both hardware access and abstraction is the basis of C++. Doing it efficiently is what distinguishes it from other languages." C++ inherits most of C's syntax . A hello world program that conforms to

576-411: A few notable exceptions such as member access ( . and .* ) and the conditional operator. The rich set of overloadable operators is central to making user-defined types in C++ seem like built-in types. Overloadable operators are also an essential part of many advanced C++ programming techniques, such as smart pointers . Overloading an operator does not change the precedence of calculations involving

672-428: A focus on usability over optimal program efficiency. Unlike low-level assembly languages , high-level languages have few, if any, language elements that translate directly into a machine's native opcodes . Other features, such as string handling routines, object-oriented language features, and file input/output, may also be present. One thing to note about high-level programming languages is that these languages allow

768-453: A fully general lambda abstraction in a programming language for the first time. "High-level language" refers to the higher level of abstraction from machine language . Rather than dealing with registers, memory addresses, and call stacks, high-level languages deal with variables, arrays, objects , complex arithmetic or Boolean expressions , subroutines and functions, loops, threads , locks, and other abstract computer science concepts, with

864-502: A new building close by at 1537 35th Street N.W., specifically to house the lab. This building was declared a National Historic Landmark in 1972. After the invention of the telephone, Bell maintained a relatively distant role with the Bell System as a whole, but continued to pursue his own personal research interests. The Bell Patent Association was formed by Alexander Graham Bell , Thomas Sanders, and Gardiner Hubbard when filing

960-574: A new outdoor plant development laboratory. Prior to Chester being established, a test plot was installed in Limon, Colorado in 1929, similar to the one in Gulfport. The three test plots at Gulfport, Limon, and Chester were outdoor facilities for preservatives and prolonging the use of telephone poles. Additionally, in 1929, a land expansion was done at the Deal Labs to 208 acres (84 ha). This added land increased

1056-416: A new, standalone compiler for C++, Cfront . In 1984, Stroustrup implemented the first stream input/output library. The idea of providing an output operator rather than a named output function was suggested by Doug McIlroy (who had previously suggested Unix pipes ). In 1985, the first edition of The C++ Programming Language was released, which became the definitive reference for the language, as there

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1152-892: A single template body is preserved. Templates are different from macros : while both of these compile-time language features enable conditional compilation, templates are not restricted to lexical substitution. Templates are aware of the semantics and type system of their companion language, as well as all compile-time type definitions, and can perform high-level operations including programmatic flow control based on evaluation of strictly type-checked parameters. Macros are capable of conditional control over compilation based on predetermined criteria, but cannot instantiate new types, recurse, or perform type evaluation and in effect are limited to pre-compilation text-substitution and text-inclusion/exclusion. In other words, macros can control compilation flow based on pre-defined symbols but cannot, unlike templates, independently instantiate new symbols. Templates are

1248-623: A specific system architecture . Abstraction penalty is the cost that high-level programming techniques pay for being unable to optimize performance or use certain hardware because they don't take advantage of certain low-level architectural resources. High-level programming exhibits features like more generic data structures and operations, run-time interpretation, and intermediate code files; which often result in execution of far more operations than necessary, higher memory consumption, and larger binary program size. For this reason, code which needs to run particularly quickly and efficiently may require

1344-488: A successor to C with Classes, which he named "C++" ( ++ being the increment operator in C) after going through several other names. New features were added, including virtual functions , function name and operator overloading , references , constants, type-safe free-store memory allocation (new/delete), improved type checking, and BCPL-style single-line comments with two forward slashes ( // ). Furthermore, Stroustrup developed

1440-444: A template, compilers substitute specific arguments for a template's parameters to generate a concrete function or class instance. Some substitutions are not possible; these are eliminated by an overload resolution policy described by the phrase " Substitution failure is not an error " (SFINAE). Templates are a powerful tool that can be used for generic programming , template metaprogramming , and code optimization, but this power implies

1536-401: A tool for static polymorphism (see below) and generic programming . In addition, templates are a compile-time mechanism in C++ that is Turing-complete , meaning that any computation expressible by a computer program can be computed, in some form, by a template metaprogram before runtime. In summary, a template is a compile-time parameterized function or class written without knowledge of

1632-622: A transmission studies site was established in Phoenixville, Pennsylvania that built, in 1929, the coaxial conductor line for first tests of long-distance transmission in various frequencies. On January 1, 1925, Bell Telephone Laboratories, Inc. was organized to consolidate the development and research activities in the communication field and allied sciences for the Bell System. Ownership was evenly shared between Western Electric and AT&T. The new company had 3600 engineers, scientists, and support staff. Its 400,000-square-foot (37,000 m ) space

1728-483: Is entered (see exceptions below) and destroyed in reverse order of creation after main() exits. The exact order of creation is not specified by the standard (though there are some rules defined below) to allow implementations some freedom in how to organize their implementation. More formally, objects of this type have a lifespan that "shall last for the duration of the program". Static storage duration objects are initialized in two phases. First, "static initialization"

1824-498: Is inherently at a slightly higher level than the microcode or micro-operations used internally in many processors. There are three general modes of execution for modern high-level languages: Note that languages are not strictly interpreted languages or compiled languages. Rather, implementations of language behavior use interpreting or compiling. For example, ALGOL 60 and Fortran have both been interpreted (even though they were more typically compiled). Similarly, Java shows

1920-399: Is performed, and only after all static initialization is performed, "dynamic initialization" is performed. In static initialization, all objects are first initialized with zeros; after that, all objects that have a constant initialization phase are initialized with the constant expression (i.e. variables initialized with a literal or constexpr ). Though it is not specified in the standard,

2016-468: Is possible for a high-level language to be directly implemented by a computer – the computer directly executes the HLL code. This is known as a high-level language computer architecture – the computer architecture itself is designed to be targeted by a specific high-level language. The Burroughs large systems were target machines for ALGOL 60 , for example. AT%26T Bell Labs The laboratory began in

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2112-664: Is standardized by the International Organization for Standardization (ISO), with the latest standard version ratified and published by ISO in October 2024 as ISO/IEC 14882:2024 (informally known as C++23 ). The C++ programming language was initially standardized in 1998 as ISO/IEC 14882:1998 , which was then amended by the C++03 , C++11 , C++14 , C++17 , and C++20 standards. The current C++23 standard supersedes these with new features and an enlarged standard library . Before

2208-400: Is that they have a lifetime that is limited to the scope of the variable. They are created and potentially initialized at the point of declaration (see below for details) and destroyed in the reverse order of creation when the scope is left. This is implemented by allocation on the stack . Local variables are created as the point of execution passes the declaration point. If the variable has

2304-810: Is usually implemented as a compiled language , and many vendors provide C++ compilers , including the Free Software Foundation , LLVM , Microsoft , Intel , Embarcadero , Oracle , and IBM . C++ was designed with systems programming and embedded , resource-constrained software and large systems in mind, with performance , efficiency, and flexibility of use as its design highlights. C++ has also been found useful in many other contexts, with key strengths being software infrastructure and resource-constrained applications, including desktop applications , video games , servers (e.g., e-commerce , web search , or databases ), and performance-critical applications (e.g., telephone switches or space probes ). C++

2400-846: The Bell Carriage House , the Bell Laboratory and the Volta Laboratory . It focused on the analysis, recording, and transmission of sound. Bell used his considerable profits from the laboratory for further research and education advancing the diffusion of knowledge relating to the deaf. This resulted in the founding of the Volta Bureau ( c.  1887 ) at the Washington, D.C. home of his father, linguist Alexander Melville Bell . The carriage house there, at 1527 35th Street N.W., became their headquarters in 1889. In 1893, Bell constructed

2496-520: The C language , and similar languages, were most often considered "high-level", as it supported concepts such as expression evaluation, parameterised recursive functions, and data types and structures, while assembly language was considered "low-level". Today, many programmers might refer to C as low-level, as it lacks a large runtime-system (no garbage collection, etc.), basically supports only scalar operations, and provides direct memory addressing; it therefore, readily blends with assembly language and

2592-524: The Charles Stark Draper Prize for Engineering, "for conceptualizing and developing the C++ programming language". In December 2022, C++ ranked third on the TIOBE index , surpassing Java for the first time in the history of the index. As of November 2024, the language ranks second after Python , with Java being in third. According to Stroustrup, "the name signifies the evolutionary nature of

2688-551: The Number Five Crossbar Switching System . In 1952, William Gardner Pfann revealed the method of zone melting , which enabled semiconductor purification and level doping. In 1953, Maurice Karnaugh developed the Karnaugh map , used for managing of Boolean algebraic expressions. In January 1954, Bell Labs built one of the first completely transistorized computer machines, TRADIC or Flyable TRADIC, for

2784-626: The Volta Prize of 50,000   francs for the invention of the telephone (equivalent to about US$ 10,000 at the time, or about $ 330,000 now), he used the award to fund the Volta Laboratory (also known as the "Alexander Graham Bell Laboratory") in Washington, D.C. in collaboration with Sumner Tainter and Bell's cousin Chichester Bell . The laboratory was variously known as the Volta Bureau ,

2880-444: The charge-coupled device (CCD), and many other optical, wireless, and wired communications technologies and systems. In 1924, Bell Labs physicist Walter A. Shewhart proposed the control chart as a method to determine when a process was in a state of statistical control. Shewhart's methods were the basis for statistical process control (SPC): the use of statistically based tools and techniques to manage and improve processes. This

2976-420: The system architecture which they were written for without major revision. This is the engineering 'trade-off' for the 'Abstraction Penalty'. Examples of high-level programming languages in active use today include Python , JavaScript , Visual Basic , Delphi , Perl , PHP , ECMAScript , Ruby , C# , Java and many others. The terms high-level and low-level are inherently relative. Some decades ago,

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3072-402: The thermal noise in a resistor was first measured by John B. Johnson , for which Harry Nyquist provided the theoretical analysis; this is now termed Johnson-Nyquist noise . During the 1920s, the one-time pad cipher was invented by Gilbert Vernam and Joseph Mauborgne at the laboratories. Bell Labs' Claude Shannon later proved that it is unbreakable. In 1928, Harold Black invented

3168-454: The 1960s, laboratory and company headquarters were moved to Murray Hill, New Jersey . Its alumni during this time include people like William Shockley , Dennis Ritchie , Claude Shannon and Willard Boyle . Bell Labs became a subsidiary of AT&T Technologies in 1984 after the Bell System was broken up . After the breakup, its funding greatly declined. In 1996, AT&T Technologies

3264-702: The Allies in World War II . The British wartime codebreaker Alan Turing visited the labs at this time, working on speech encryption and meeting Claude Shannon . Bell Labs Quality Assurance Department gave the world and the United States such statisticians as Walter A. Shewhart , W. Edwards Deming , Harold F. Dodge , George D. Edwards , Harry Romig, R. L. Jones, Paul Olmstead, E.G.D. Paterson, and Mary N. Torrey . During World War II, Emergency Technical Committee – Quality Control, drawn mainly from Bell Labs' statisticians,

3360-512: The Bell System by 1889. American Bell held a controlling interest in Western Electric (which was the manufacturing arm of the business) whereas AT&T was doing research into the service providers. In 1896, Western Electric bought property at 463 West Street to centralize the manufacturers and engineers which had been supplying AT&T with such technology as telephones, telephone exchange switches and transmission equipment. During

3456-595: The C standard is also a valid C++ hello world program. The following is Bjarne Stroustrup's version of the Hello world program that uses the C++ Standard Library stream facility to write a message to standard output : As in C, C++ supports four types of memory management : static storage duration objects, thread storage duration objects, automatic storage duration objects, and dynamic storage duration objects. Static storage duration objects are created before main()

3552-464: The C++ language , including Linus Torvalds , Richard Stallman , Joshua Bloch , Ken Thompson , and Donald Knuth . In 1979, Bjarne Stroustrup , a Danish computer scientist , began work on " C with Classes ", the predecessor to C++. The motivation for creating a new language originated from Stroustrup's experience in programming for his PhD thesis. Stroustrup found that Simula had features that were very helpful for large software development, but

3648-497: The United States Air Force with 10,358 germanium point-contact diodes and 684 Bell Labs Type 1734 Type A cartridge transistors. The design team was led by electrical engineer Jean Howard Felker with James R. Harris and Louis C. Brown ("Charlie Brown") as the lead engineers on the project, which started in 1951. The device took only 3 cubic-feet and consumed 100 watt power for its small and low powered design in comparison to

3744-597: The Voder being demonstrated at the 1939 New York World's Fair. Bell researcher Clinton Davisson shared the Nobel Prize in Physics with George Paget Thomson for the discovery of electron diffraction , which helped lay the foundation for solid-state electronics . In the early 1940s, the photovoltaic cell was developed by Russell Ohl . In 1943, Bell developed SIGSALY , the first digital scrambled speech transmission system, used by

3840-760: The Whippany site was purchased by Bayer ). The largest grouping of people in the company was in Illinois , at Naperville - Lisle , in the Chicago area, which had the largest concentration of employees (about 11,000) prior to 2001. There also were groups of employees in Indianapolis , Indiana; Columbus, Ohio ; North Andover, Massachusetts ; Allentown, Pennsylvania ; Reading, Pennsylvania ; and Breinigsville, Pennsylvania ; Burlington, North Carolina (1950s–1970s, moved to Greensboro 1980s) and Westminster, Colorado . Since 2001, many of

3936-633: The allocated memory. The C++ Core Guidelines advise against using new directly for creating dynamic objects in favor of smart pointers through make_unique < T > for single ownership and make_shared < T > for reference-counted multiple ownership, which were introduced in C++11. C++ templates enable generic programming . C++ supports function, class, alias, and variable templates. Templates may be parameterized by types, compile-time constants, and other templates. Templates are implemented by instantiation at compile-time. To instantiate

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4032-593: The center of the galaxy . In 1931 and 1932, the labs made experimental high fidelity, long playing, and even stereophonic recordings of the Philadelphia Orchestra , conducted by Leopold Stokowski . In 1933, stereo signals were transmitted live from Philadelphia to Washington, D.C. In 1937, the vocoder , an electronic speech compression device, or codec, and the Voder , the first electronic speech synthesizer , were developed and demonstrated by Homer Dudley ,

4128-501: The changes from C." This name is credited to Rick Mascitti (mid-1983) and was first used in December 1983. When Mascitti was questioned informally in 1992 about the naming, he indicated that it was given in a tongue-in-cheek spirit. The name comes from C's ++ operator (which increments the value of a variable ) and a common naming convention of using "+" to indicate an enhanced computer program. During C++'s development period,

4224-432: The class ("friends"). A protected member is accessible to members of classes that inherit from the class in addition to the class itself and any friends. The object-oriented principle ensures the encapsulation of all and only the functions that access the internal representation of a type. C++ supports this principle via member functions and friend functions, but it does not enforce it. Programmers can declare parts or all of

4320-418: The class. This can hide the details of data implementation, allowing the designer to later fundamentally change the implementation without changing the interface in any way. Inheritance allows one data type to acquire properties of other data types. Inheritance from a base class may be declared as public, protected, or private. This access specifier determines whether unrelated and derived classes can access

4416-530: The decade. Shannon was also the founder of modern cryptography with his 1949 paper Communication Theory of Secrecy Systems . The 1950s also saw developments based upon information theory . The central development was binary code systems. Efforts concentrated on the prime mission of supporting the Bell System with engineering advances, including the N-carrier system, TD microwave radio relay , direct distance dialing , E- repeater , wire spring relay , and

4512-473: The difficulty of trying to apply these labels to languages, rather than to implementations; Java is compiled to bytecode which is then executed by either interpreting (in a Java virtual machine (JVM)) or compiling (typically with a just-in-time compiler such as HotSpot , again in a JVM). Moreover, compiling, transcompiling, and interpreting is not strictly limited to only a description of the compiler artifact (binary executable or IL assembly). Alternatively, it

4608-520: The early 1920s, a few outdoor facilities and radio communications development facilities were developed. In 1925, the test plot studies were established at Gulfport, Mississippi , where there were numerous telephone pole samples established for wood preservation. At the Deal, New Jersey location, work was done on ship-to-shore radio telephony. In 1926, in the Whippany section of Hanover Township, New Jersey , land

4704-597: The early 20th century, several historically significant laboratories were established. In 1915, the first radio transmissions were made from a shack in Montauk, Long Island . That same year, tests were performed on the first transoceanic radio telephone at a house in Arlington County, Virginia . A radio reception laboratory was established in 1919 in the Cliffwood section of Aberdeen Township, New Jersey . Additionally for 1919,

4800-452: The facility for radio transmission studies. The beginning of 1930s, established three facilities with radio communications experiments and chemical aspects testing. By 1939, the Summit, New Jersey , chemical laboratory was nearly 10 years established in a three-story building conducted experiments in corrosion, using various fungicides tests on cables, metallic components, or wood. For 1929, land

4896-572: The first transatlantic communications cable to carry telephone conversations, was laid between Scotland and Newfoundland in a joint effort by AT&T, Bell Laboratories, and British and Canadian telephone companies. In 1957, Max Mathews created MUSIC , one of the first computer programs to play electronic music . Robert C. Prim and Joseph Kruskal developed new greedy algorithms that revolutionized computer network design . In 1957 Frosch and Derick, using masking and predeposition, were able to manufacture silicon dioxide field effect transistors;

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4992-722: The first patents for the telephone in 1876. Bell Telephone Company, the first telephone company, was formed a year later. It later became a part of the American Bell Telephone Company. In 1884, the American Bell Telephone Company created the Mechanical Department from the Electrical and Patent Department formed a year earlier. American Telephone & Telegraph Company (AT&T) and its own subsidiary company took control of American Bell and

5088-508: The first time as ISO/IEC 14882:1998 , which is informally known as C++98 . In 2003, it published a new version of the C++ standard called ISO/IEC 14882:2003 , which fixed problems identified in C++98. The next major revision of the standard was informally referred to as "C++0x", but it was not released until 2011. C++11 (14882:2011) included many additions to both the core language and the standard library. In 2014, C++14 (also known as C++1y)

5184-434: The former locations have been scaled down or closed. Bell's Holmdel research and development lab , a 1,900,000-square-foot (180,000 m ) structure set on 473 acres (191 ha), was closed in 2007. The mirrored-glass building was designed by Eero Saarinen . In August 2013, Somerset Development bought the building, intending to redevelop it into a mixed commercial and residential project. A 2012 article expressed doubt on

5280-605: The four features commonly present in OOP (and some non-OOP) languages: abstraction , encapsulation , inheritance , and polymorphism . One distinguishing feature of C++ classes compared to classes in other programming languages is support for deterministic destructors , which in turn provide support for the Resource Acquisition is Initialization (RAII) concept. Encapsulation is the hiding of information to ensure that data structures and operators are used as intended and to make

5376-478: The goal of aggregating the most popular constructs with new or improved features. An example of this is Scala which maintains backward compatibility with Java , meaning that programs and libraries written in Java will continue to be usable even if a programming shop switches to Scala; this makes the transition easier and the lifespan of such high-level coding indefinite. In contrast, low-level programs rarely survive beyond

5472-605: The higher abstraction may allow for more powerful techniques providing better overall results than their low-level counterparts in particular settings. High-level languages are designed independent of a specific computing system architecture . This facilitates executing a program written in such a language on any computing system with compatible support for the Interpreted or JIT program. High-level languages can be improved as their designers develop improvements. In other cases, new high-level languages evolve from one or more others with

5568-426: The inherited public and protected members of the base class. Only public inheritance corresponds to what is usually meant by "inheritance". The other two forms are much less frequently used. If the access specifier is omitted, a "class" inherits privately, while a "struct" inherits publicly. Base classes may be declared as virtual; this is called virtual inheritance . Virtual inheritance ensures that only one instance of

5664-432: The initial standardization in 1998, C++ was developed by Stroustrup at Bell Labs since 1979 as an extension of the C language; he wanted an efficient and flexible language similar to C that also provided high-level features for program organization. Since 2012, C++ has been on a three-year release schedule with C++26 as the next planned standard. Despite its widespread adoption, some notable programmers have criticized

5760-599: The language features described above. Compile-time polymorphism does not allow for certain run-time decisions, while runtime polymorphism typically incurs a performance penalty. High-level programming language In computer science , a high-level programming language is a programming language with strong abstraction from the details of the computer . In contrast to low-level programming languages , it may use natural language elements , be easier to use, or may automate (or even hide entirely) significant areas of computing systems (e.g. memory management ), making

5856-485: The language had been referred to as "new C" and "C with Classes" before acquiring its final name. Throughout C++'s life, its development and evolution has been guided by a set of principles: C++ is standardized by an ISO working group known as JTC1/SC22/WG21 . So far, it has published seven revisions of the C++ standard and is currently working on the next revision, C++26 . In 1998, the ISO working group standardized C++ for

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5952-507: The language was too slow for practical use, while BCPL was fast but too low-level to be suitable for large software development. When Stroustrup started working in AT&;T Bell Labs , he had the problem of analyzing the UNIX kernel with respect to distributed computing . Remembering his PhD experience, Stroustrup set out to enhance the C language with Simula -like features. C was chosen because it

6048-681: The late 19th century as the Western Electric Engineering Department, located at 463 West Street in New York City. After years of conducting research and development under Western Electric , a Bell subsidiary, the Engineering Department was reformed into Bell Telephone Laboratories in 1925 and placed under the shared ownership of Western Electric and the American Telephone and Telegraph Company (AT&T). In

6144-597: The later Bell Laboratories locations in New Jersey were Holmdel Township , Crawford Hill , the Deal Test Site , Freehold , Lincroft , Long Branch , Middletown , Neptune Township , Princeton , Piscataway , Red Bank , Chester Township , and Whippany . Of these, Murray Hill and Crawford Hill remain in existence (the Piscataway and Red Bank locations were transferred to and are now operated by Telcordia Technologies and

6240-401: The location performed precision frequency-measuring apparatus, field strength measurements, and conducted radio interference. By the early 1940s, Bell Labs engineers and scientists had begun to move to other locations away from the congestion and environmental distractions of New York City, and in 1967 Bell Laboratories headquarters was officially relocated to Murray Hill, New Jersey . Among

6336-534: The machine level of CPUs and microcontrollers . Also, in the introduction chapter of The C Programming Language (second edition) by Brian Kernighan and Dennis Ritchie , C is described as "not a very high level" language. Assembly language may itself be regarded as a higher level (but often still one-to-one if used without macros ) representation of machine code , as it supports concepts such as constants and (limited) expressions, sometimes even variables, procedures, and data structures . Machine code , in turn,

6432-482: The negative feedback system commonly used in amplifiers. Later, Harry Nyquist analyzed Black's design rule for negative feedback. This work was published in 1932 and became known as the Nyquist criterion . In 1931, a foundation for radio astronomy was laid by Karl Jansky during his work investigating the origins of static on long-distance shortwave communications . He discovered that radio waves were being emitted from

6528-815: The number of base classes to one (interfaces, unlike classes, provide only declarations of member functions, no implementation or member data). An interface as in C# and Java can be defined in C++ as a class containing only pure virtual functions, often known as an abstract base class or "ABC". The member functions of such an abstract base class are normally explicitly defined in the derived class, not inherited implicitly. C++ virtual inheritance exhibits an ambiguity resolution feature called dominance . C++ provides more than 35 operators, covering basic arithmetic, bit manipulation, indirection, comparisons, logical operations and others. Almost all operators can be overloaded for user-defined types, with

6624-556: The operator, nor does it change the number of operands that the operator uses (any operand may however be ignored by the operator, though it will be evaluated prior to execution). Overloaded " && " and " || " operators lose their short-circuit evaluation property. Polymorphism enables one common interface for many implementations, and for objects to act differently under different circumstances. C++ supports several kinds of static (resolved at compile-time ) and dynamic (resolved at run-time ) polymorphisms , supported by

6720-425: The order of initialization between compilation units. Variables of this type are very similar to static storage duration objects. The main difference is the creation time is just before thread creation, and destruction is done after the thread has been joined. The most common variable types in C++ are local variables inside a function or block, and temporary variables. The common feature about automatic variables

6816-452: The parent object is created. Array members are initialized from 0 to the last member of the array in order. Member variables are destroyed when the parent object is destroyed in the reverse order of creation. i.e. If the parent is an "automatic object" then it will be destroyed when it goes out of scope which triggers the destruction of all its members. Temporary variables are created as the result of expression evaluation and are destroyed when

6912-419: The process of developing a program simpler and more understandable than when using a lower-level language. The amount of abstraction provided defines how "high-level" a programming language is. In the 1960s, a high-level programming language using a compiler was commonly called an autocode . Examples of autocodes are COBOL and Fortran . The first high-level programming language designed for computers

7008-620: The programmer to be detached and separated from the machine. That is, unlike low-level languages like assembly or machine language, high-level programming can amplify the programmer's instructions and trigger a lot of data movements in the background without their knowledge. The responsibility and power of executing instructions have been handed over to the machine from the programmer. High-level languages intend to provide features that standardize common tasks, permit rich debugging, and maintain architectural agnosticism; while low-level languages often produce more efficient code through optimization for

7104-430: The representation of a type to be public, and they are allowed to make public entities not part of the representation of a type. Therefore, C++ supports not just object-oriented programming, but other decomposition paradigms such as modular programming . It is generally considered good practice to make all data private or protected, and to make public only those functions that are part of a minimal interface for users of

7200-497: The result was not published until 1950. In 1948, " A Mathematical Theory of Communication ", one of the founding works in information theory , was published by Claude Shannon in the Bell System Technical Journal . It built in part on earlier work in the field by Bell researchers Harry Nyquist and Ralph Hartley , but went much further. Bell Labs also introduced a series of increasingly complex calculators through

7296-501: The specific arguments used to instantiate it. After instantiation, the resulting code is equivalent to code written specifically for the passed arguments. In this manner, templates provide a way to decouple generic, broadly applicable aspects of functions and classes (encoded in templates) from specific aspects (encoded in template parameters) without sacrificing performance due to abstraction. C++ introduces object-oriented programming (OOP) features to C. It offers classes , which provide

7392-555: The standard library further, and providing more facilities to C++ programmers. After a minor C++14 update released in December 2014, various new additions were introduced in C++17 . After becoming finalized in February 2020, a draft of the C++20 standard was approved on 4 September 2020, and officially published on 15 December 2020. On January 3, 2018, Stroustrup was announced as the 2018 winner of

7488-408: The statement containing the expression has been fully evaluated (usually at the ; at the end of a statement). These objects have a dynamic lifespan and can be created directly with a call to new and destroyed explicitly with a call to delete . C++ also supports malloc and free , from C, but these are not compatible with new and delete . Use of new returns an address to

7584-479: The static initialization phase can be completed at compile time and saved in the data partition of the executable. Dynamic initialization involves all object initialization done via a constructor or function call (unless the function is marked with constexpr , in C++11). The dynamic initialization order is defined as the order of declaration within the compilation unit (i.e. the same file). No guarantees are provided about

7680-464: The success of the newly named Bell Works site, but several large tenants had announced plans to move in through 2016 and 2017. Bell Lab's 1974 corporate directory listed 22 labs in the United States, located in: Nokia Bell Lab's 2024 website pictured 10 labs, located in: Also listed as research locations without additional information was Sunnyvale, California , US and Tampere, Finland . The Naperville, Illinois Bell Labs location near Chicago

7776-470: The usage model more obvious to the developer. C++ provides the ability to define classes and functions as its primary encapsulation mechanisms. Within a class, members can be declared as either public, protected, or private to explicitly enforce encapsulation. A public member of the class is accessible to any function. A private member is accessible only to functions that are members of that class and to functions and classes explicitly granted access permission by

7872-549: The use of a lower-level language, even if a higher-level language would make the coding easier. In many cases, critical portions of a program mostly in a high-level language can be hand-coded in assembly language , leading to a much faster, more efficient, or simply reliably functioning optimised program . However, with the growing complexity of modern microprocessor architectures, well-designed compilers for high-level languages frequently produce code comparable in efficiency to what most low-level programmers can produce by hand, and

7968-470: The vacuum tube designs of the times. The device could be installed in a B-52 Stratofortress Bomber and had a performance up to one million logical operations a second. The flyable program used a Mylar sheet with punched holes, instead of the removable plugboard. In 1954, the first modern solar cell was invented at Bell Laboratories. In 1955, Carl Frosch and Lincoln Derick discovered semiconductor surface passivation by silicon dioxide. In 1956 TAT-1 ,

8064-678: Was Plankalkül , created by Konrad Zuse . However, it was not implemented in his time, and his original contributions were largely isolated from other developments due to World War II , aside from the language's influence on the "Superplan" language by Heinz Rutishauser and also to some degree ALGOL . The first significantly widespread high-level language was Fortran , a machine-independent development of IBM's earlier Autocode systems. The ALGOL family, with ALGOL 58 defined in 1958 and ALGOL 60 defined in 1960 by committees of European and American computer scientists, introduced recursion as well as nested functions under lexical scope . ALGOL 60

8160-555: Was acquired and established for the development of a 50-kilowatt broadcast transmitter. In 1931, Whippany increased with 75 acres (30 ha) added from a nearby property. In 1928, a 15-acre (6.1 ha) site in Chester Township, New Jersey , was leased for outdoor tests, though the facility became inadequate for such purposes. In 1930, the Chester location required the purchase of an additional 85 acres (34 ha) of land to be used for

8256-451: Was also the first language with a clear distinction between value and name-parameters and their corresponding semantics . ALGOL also introduced several structured programming concepts, such as the while-do and if-then-else constructs and its syntax was the first to be described in formal notation – Backus–Naur form (BNF). During roughly the same period, COBOL introduced records (also called structs) and Lisp introduced

8352-495: Was considered the Chicago Innovation Center and hosted Nokia's second annual Algorithm World event in 2022. Bell Laboratories was, and is, regarded by many as the premier research facility of its type, developing a wide range of revolutionary technologies, including radio astronomy , the transistor , the laser , information theory , the operating system Unix , the programming languages C and C++ , solar cells ,

8448-399: Was expanded with a new building occupying about one quarter of a city block. The first chairman of the board of directors was John J. Carty , AT&T's vice president, and the first president was Frank B. Jewett , also a board member, who stayed there until 1940. The operations were directed by E. B. Craft, executive vice-president, and formerly chief engineer at Western Electric. In

8544-405: Was general-purpose, fast, portable, and widely used. In addition to C and Simula's influences, other languages influenced this new language, including ALGOL 68 , Ada , CLU , and ML . Initially, Stroustrup's "C with Classes" added features to the C compiler, Cpre, including classes , derived classes , strong typing , inlining , and default arguments . In 1982, Stroustrup started to develop

8640-460: Was instrumental in advancing Army and Navy ammunition acceptance and material sampling procedures. In 1947, the transistor , arguably the most important invention developed by Bell Laboratories, was invented by John Bardeen , Walter Houser Brattain , and William Bradford Shockley (who subsequently shared the Nobel Prize in Physics in 1956). In 1947, Richard Hamming invented Hamming codes for error detection and correction . For patent reasons,

8736-421: Was not yet an official standard. The first commercial implementation of C++ was released in October of the same year. In 1989, C++ 2.0 was released, followed by the updated second edition of The C++ Programming Language in 1991. New features in 2.0 included multiple inheritance, abstract classes, static member functions, const member functions , and protected members. In 1990, The Annotated C++ Reference Manual

8832-468: Was published. This work became the basis for the future standard. Later feature additions included templates , exceptions , namespaces , new casts , and a Boolean type . In 1998, C++98 was released, standardizing the language, and a minor update ( C++03 ) was released in 2003. After C++98, C++ evolved relatively slowly until, in 2011, the C++11 standard was released, adding numerous new features, enlarging

8928-797: Was purchased in Holmdel Township, New Jersey , for a radio reception laboratory to replace the Cliffwood location that had been in operation since 1919. In 1930, the Cliffwood location was ending its operations as Holmdel was established. Whereas, in 1930, a location in Mendham Township, New Jersey , was established to continue radio receiver developments farther from the Whippany location and eliminate transmitter interference at that facility with developments. The Mendham location worked on communication equipment and broadcast receivers. These devices were used for marine, aircraft, and police services as well as

9024-660: Was released as a small extension to C++11, featuring mainly bug fixes and small improvements. The Draft International Standard ballot procedures completed in mid-August 2014. After C++14, a major revision C++17 , informally known as C++1z, was completed by the ISO C++ committee in mid July 2017 and was approved and published in December 2017. As part of the standardization process, ISO also publishes technical reports and specifications : More technical specifications are in development and pending approval, including new set of concurrency extensions. The C++ language has two main components:

9120-520: Was spun off and renamed to Lucent Technologies, who used the Murray Hill site as their headquarters. Bell Laboratories was split as well, with part of it going to AT&T as AT&T Laboratories . In 2006, Lucent merged with French telecommunications company Alcatel to form Alcatel-Lucent , which was in turn acquired by Nokia in 2016. In 1880, when the French government awarded Alexander Graham Bell

9216-427: Was the origin of the modern quality control movement, including Six Sigma . In 1926, the laboratories invented an early synchronous-sound motion picture system, in competition with Fox Movietone and DeForest Phonofilm . In 1927, a Bell team headed by Herbert E. Ives successfully transmitted long-distance 128-line television images of Secretary of Commerce Herbert Hoover from Washington to New York. In 1928

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