Consider the function subString(), whose C99 prototype follows:

bool subString(char *haystack, char *needle); The purpose of the function is to determine if the character string pointed to by needle is a substring of the character string pointed to by haystack. The function returns true if needle is a substring of haystack (i.e. needle completely appears within haystack), and false otherwise. You may assume that both haystack and needle are valid pointers to strings.Write the function subString() in C99.Do not simply call the similar C99 function strstr().