/in/foo.cc: In function 'int main()':
/in/foo.cc:49:10: error: 'a' was not declared in this scope
  s3(A,B);a
          ^
/in/foo.cc:46:10: warning: unused variable 's' [-Wunused-variable]
  int A,B,s=0,i;
          ^
/in/foo.cc:46:14: warning: unused variable 'i' [-Wunused-variable]
  int A,B,s=0,i;
              ^