/in/foo.c: In function 'main':
/in/foo.c:5:5: error: 'intA' undeclared (first use in this function); did you mean 'int'?
     intA,B;
     ^~~~
     int
/in/foo.c:5:5: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:5:10: error: 'B' undeclared (first use in this function)
     intA,B;
          ^
/in/foo.c:5:9: warning: left-hand operand of comma expression has no effect [-Wunused-value]
     intA,B;
         ^
/in/foo.c:6:2: error: 'cin' undeclared (first use in this function); did you mean 'main'?
  cin>>A>>B;
  ^~~
  main
/in/foo.c:6:7: error: 'A' undeclared (first use in this function)
  cin>>A>>B;
       ^
/in/foo.c:7:2: error: 'cout' undeclared (first use in this function)
  cout<<A+B;
  ^~~~