/in/foo.c: In function 'main':
/in/foo.c:7:2: error: 'cin' undeclared (first use in this function)
    7 |  cin>>a;
      |  ^~~
/in/foo.c:7:2: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:11:4: error: 'cout' undeclared (first use in this function)
   11 |    cout<<" ";
      |    ^~~~
/in/foo.c:14:10: error: 'c' undeclared (first use in this function)
   14 |    cout<<c;
      |          ^
/in/foo.c:16:9: error: 'endl' undeclared (first use in this function)
   16 |   cout<<endl:
      |         ^~~~
/in/foo.c:16:13: error: expected ';' before ':' token
   16 |   cout<<endl:
      |             ^
      |             ;