foo.cc: In function ‘int main()’:
foo.cc:9:2: error: ‘cout’ was not declared in this scope
    9 |  cout<<a<<" "<<b<<" "<<c<<endl
      |  ^~~~
foo.cc:2:1: note: ‘std::cout’ is defined in header ‘<iostream>’; this is probably fixable by adding ‘#include <iostream>’
    1 | #include <stdio.h>
  +++ |+#include <iostream>
    2 | using namespace std;
foo.cc:9:27: error: ‘endl’ was not declared in this scope
    9 |  cout<<a<<" "<<b<<" "<<c<<endl
      |                           ^~~~
foo.cc:2:1: note: ‘std::endl’ is defined in header ‘<ostream>’; this is probably fixable by adding ‘#include <ostream>’
    1 | #include <stdio.h>
  +++ |+#include <ostream>
    2 | using namespace std;