foo.cc: In function 'int main()':
foo.cc:9:17: error: 'cin' was not declared in this scope
    9 |                 cin>>a>>b;
      |                 ^~~
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:15:9: error: 'cout' was not declared in this scope
   15 |         cout<<weekday<<endl;
      |         ^~~~
foo.cc:15:9: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
foo.cc:15:24: error: 'endl' was not declared in this scope
   15 |         cout<<weekday<<endl;
      |                        ^~~~
foo.cc:2:1: note: 'std::endl' is defined in header '<ostream>'; did you forget to '#include <ostream>'?
    1 | #include <stdio.h>
  +++ |+#include <ostream>
    2 | using namespace std;

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