foo.cpp: In function 'int main()':
foo.cpp:4:10: error: 'cout' was not declared in this scope
 int a,b; cout<<a%b<<endl; return 0; }
          ^
foo.cpp:4:21: error: 'endl' was not declared in this scope
 int a,b; cout<<a%b<<endl; return 0; }
                     ^