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String functions are used in computer programming languages to manipulate a string or query information about a string (some do both).. Most programming languages that have a string datatype will have some string functions although there may be other low-level ways within each language to handle strings directly.
The term string also does not always refer to a sequence of Unicode characters, instead referring to a sequence of bytes. For example, x86-64 has string instructions to move, set, search, or compare a sequence of items, where an item could be 1, 2, 4, or 8 bytes long. [26]
The length of a string can also be stored explicitly, for example by prefixing the string with the length as a byte value. This convention is used in many Pascal dialects; as a consequence, some people call such a string a Pascal string or P-string. Storing the string length as byte limits the maximum string length to 255.
The length of a string is the number of code units before the zero code unit. [1] The memory occupied by a string is always one more code unit than the length, as space is needed to store the zero terminator. Generally, the term string means a string where the code unit is of type char, which is exactly 8 bits on all modern machines.
UTF-8-encoded, preceded by varint-encoded integer length of string in bytes Repeated value with the same tag or, for varint-encoded integers only, values packed contiguously and prefixed by tag and total byte length — Smile \x21
On some PowerPC systems, [11] long double is implemented as a double-double arithmetic, where a long double value is regarded as the exact sum of two double-precision values, giving at least a 106-bit precision; with such a format, the long double type does not conform to the IEEE floating-point standard.
But it comes with a performance penalty for string literals, as std::string usually allocates memory dynamically, and must copy the C-style string literal to it at run time. Before C++11, there was no literal for C++ strings (C++11 allows "this is a C++ string"s with the s at the end of the literal), so the normal constructor syntax was used ...
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]