size of array

#define num(x) (sizeof (x) / sizeof (*x))

int main(){

   int number[10] = {1,1,1,1,1,1};
   char *teststr[20] = {"","","","","","","","",""};

   printf("Size of number[10] is %d\n", (int)num(number));
   printf("Size of teststr[20] is %d\n", (int)num(teststr));
   return 0;
}