Declaration: char *strnset(char *s, int ch, size_t n); Sets the first n characters of s to ch #include <stdio.h> #include <string.h> int main(void) { char *string = "abcdefghijklmnopqrstuvwxyz"; char letter = 'x'; printf("string before strnset: %s\n", string); strnset(string, letter, 13); printf("string after strnset: %s\n", string); return 0; } Output: string before strnset: abcdefghijklmnopqrstuvwxyz string after strnset: xxxxxxxxxxxxxnopqrstuvwxyz