Описание тега null-terminated

The C language doesn't have a built-in string type, instead strings are represented by a contiguous sequence of characters followed by a null-terminator (a character with value zero) and are referred to by a pointer to the first character of the sequence. The length of the string is therefore implied by the position of the null terminator, rather than being stored explicitly. Operations on null-terminated strings use a pointer to the sequence and interpret all the characters up to the null-terminator as the contents of the string.

This contrasts with string types in other languages which might be represented by an abstract data type or as a pointer to data where the length is stored in one or more bytes at the start of the string.