/in/foo.cc: In function 'int main()':
/in/foo.cc:30:6: warning: unused variable 'x' [-Wunused-variable]
  int x,y,z,k;
      ^
/in/foo.cc:30:8: warning: unused variable 'y' [-Wunused-variable]
  int x,y,z,k;
        ^
/in/foo.cc:30:10: warning: unused variable 'z' [-Wunused-variable]
  int x,y,z,k;
          ^