Cstring

A C-style string is a sequence of characters stored in a contiguous memory buffer and terminated by a null character (NUL, '\0'). In C there is no distinct string type; strings are represented as arrays of char. A C string ends at the first null byte, which marks its end for functions that manipulate strings.

Standard library functions for C strings are defined in string.h and include: strlen to compute length, strcpy/strncpy to copy, strcat/strncat to concatenate, and strcmp/strncmp to compare, and strchr/strstr to search. Memory-move and copy functions such as memcpy and memmove operate on raw bytes. These routines assume proper null termination and adequate destination space.

Because C strings do not perform bounds checking, unsafe use can cause buffer overflows, reading past the end, or missing terminators. Safe practices include using bounded variants when available, ensuring sufficient destination size, and using snprintf for formatting. With UTF-8, strlen counts bytes, not characters, so length calculations may not reflect user-perceived length.

In C++, the same functions are available in <cstring> and reside in the std namespace. C++ also provides std::string, a high-level string type that manages memory automatically. C strings remain important for interoperability with C libraries and system interfaces.

See also: C standard library, string.h, std::string.