/in/foo.c: In function 'power':
/in/foo.c:30:15: warning: passing argument 2 of 'Mul' makes integer from pointer without a cast [-Wint-conversion]
     Mul(temp, temp, result);
               ^~~~
/in/foo.c:5:6: note: expected 'int' but argument is of type 'char *'
 void Mul(char* num1, int num2, char* result) {
      ^~~
/in/foo.c:32:21: warning: implicit declaration of function 'atoi' [-Wimplicit-function-declaration]
         Mul(result, atoi(x), temp);
                     ^~~~