编写一个函数int loc(char * a, char *b)，确认a,b两个字符串中一个字符串是否包含另一个字符串，如果包含则返回被包含字符串在另外一字符串的起始位置，如果不包含则返回-1。请在主函数中让用户输入两个字符串，调用该函数进行判断，并输出判断结果。-Write a function int loc (char* a, char* b), confirmed that a, b two string if a string contains another string, if contains the string back to be included in another string starting location, if the return does not contain-1. Please in the main function of allowing the user to enter two strings, call the function to determine and judge the outcome of the output.