foo.cc: In function 'int main()':
foo.cc:9:5: error: 'cin' was not declared in this scope
    9 |     cin>>x1>>" ">>n1>>" ">>x2>>" ">>n2;
      |     ^~~
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;
foo.cc: At global scope:
foo.cc:12:2: error: expected unqualified-id before 'return'
   12 |  return 0;
      |  ^~~~~~

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