/in/foo.cc: In function 'int main()':
/in/foo.cc:6:9: error: 'cin' was not declared in this scope
    6 |         cin>>n;
      |         ^~~
/in/foo.cc:2:1: note: 'std::cin' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
    1 | #include<stdio.h>
  +++ |+#include <iostream>
    2 | using namespace std;