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The number of reserved words varies widely from one language to another: C has about 30 while COBOL has about 400. Note that a few languages do not have any reserved words. Fortran and PL/I identify keywords by context, while Algol 60 and Algol 68 generally use stropping to distinguish keywords from programmer-defined identifiers, e.g. .if or ...
The std::string class is the standard representation for a text string since C++98. The class provides some typical string operations like comparison, concatenation, find and replace, and a function for obtaining substrings. An std::string can be constructed from a C-style string, and a C-style string can also be obtained from one. [7]
A string is defined as a contiguous sequence of code units terminated by the first zero code unit (often called the NUL code unit). [1] This means a string cannot contain the zero code unit, as the first one seen marks the end of the string. The length of a string is the number of code units before the zero code unit. [1]
The choice of a variable name should be mnemonic — that is, designed to indicate to the casual observer the intent of its use. One-character variable names should be avoided except for temporary "throwaway" variables. Common names for temporary variables are i, j, k, m, and n for integers; c, d, and e for characters. int i;
Name mangling is only one of several application binary interface (ABI) details that need to be decided and observed by a C++ implementation. Other ABI aspects like exception handling , virtual table layout, structure, and stack frame padding also cause differing C++ implementations to be incompatible.
The C++ Standard Library provides several generic containers, functions to use and manipulate these containers, function objects, generic strings and streams (including interactive and file I/O), support for some language features, and functions for common tasks such as finding the square root of a number.
Since the C99 standard, C supports escape sequences that denote Unicode code points, called universal character names. They have the form \uhhhh or \Uhhhhhhhh, where h stands for a hex digit. Unlike other escape sequences, a universal character name may expand into more than one code unit.
All logical operators exist in C and C++ and can be overloaded in C++, albeit the overloading of the logical AND and logical OR is discouraged, because as overloaded operators they behave as ordinary function calls, which means that both of their operands are evaluated, so they lose their well-used and expected short-circuit evaluation property ...