/in/foo.cc: In function 'int main()':
/in/foo.cc:17:8: warning: unused variable 'j' [-Wunused-variable]
  int i,j;
        ^
/in/foo.cc:16:16: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&t);
                ^
/in/foo.cc:20:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&num[i].x,&num[i].y);
                                    ^