/in/foo.cc: In function 'int main()':
/in/foo.cc:5:17: error: '$a' was not declared in this scope
  scanf("%d%d%d",$a,$b,%c);
                 ^~
/in/foo.cc:5:20: error: '$b' was not declared in this scope
  scanf("%d%d%d",$a,$b,%c);
                    ^~
/in/foo.cc:5:23: error: expected primary-expression before '%' token
  scanf("%d%d%d",$a,$b,%c);
                       ^