/in/foo.cc: In function 'int main()':
/in/foo.cc:6:15: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'int' [-Wformat=]
  scanf("%d", a)
               ^
/in/foo.cc:7:2: error: expected ';' before 's'
  s = a * a
  ^
/in/foo.cc:5:13: warning: unused variable 's' [-Wunused-variable]
  int a = 0, s = 0;
             ^