Someone

int charreplace(char * string, int find_character, int replace_character) {

	int i, length, found;
	
	length = strlen(string);
	found = 0;

	for (i = 0; i < length; i++) {
		if (string[i] == find_character) {
			string[i] = replace_character;
			found++;
		}
	}

	return found;
}