The strstr() function locates the first occurrence of the nul-terminated string little in the nul-terminated string big.
The strcasestr() function is similar to strstr(), but ignores the case of both strings.
RETURN VALUES
If little is an empty string, big is returned; if little occurs nowhere in big, NULL is returned; otherwise a pointer to the first character of the first occurrence of little is returned.
EXAMPLES
The following sets the pointer ptr to the “Bar Baz” portion of largestring: