/in/foo.cc: In function 'int main()':
/in/foo.cc:67:12: warning: unused variable 'x3' [-Wunused-variable]
  int x1,x2,x3,x4,y1,y2,y3,y4;
            ^~
/in/foo.cc:67:15: warning: unused variable 'x4' [-Wunused-variable]
  int x1,x2,x3,x4,y1,y2,y3,y4;
               ^~
/in/foo.cc:67:24: warning: unused variable 'y3' [-Wunused-variable]
  int x1,x2,x3,x4,y1,y2,y3,y4;
                        ^~
/in/foo.cc:67:27: warning: unused variable 'y4' [-Wunused-variable]
  int x1,x2,x3,x4,y1,y2,y3,y4;
                           ^~