C Standard Library Inbuilt Function

With every C compiler, a large set of useful string handling library function are provided.
Below lists the more commonly used functions along with their name and features as:

Function name	Features
strlen()	Calculate length of string
strcpy()	Copy from one string to another
strncpy()	Copies first n characters of one string into another
strcat()	Appends one string at the end of another
strncat()	Appends first n characters of a string at the end of another
strcmp()	Compares two string
strncmp()	Compares first n characters of two string
strcmpi()	Compares two string with ignore the case
stricmp	Compares two string with ignore the case(identical to strcmpi)
strnicmp	Compares first n characters of two string with ignore the case
strlwr	Convert a string to lowercase
strupr	Convert a string to uppercase
strrev	Reverse string
strdup	Duplicate a string
strchr	Finds first occurrence of a given character in a string
strrchr	Finds last occurrence of a given character in a string
strstr	Finds first occurrence of a given string in another string
strset	Sets all characters of string to a given character
strnset	Sets first n characters of a string to a given character

Table: Standard Library String Function in C Language

(For syntax, example and use of above function, click at related function name.)