/in/foo.cc: In function 'int main()':
/in/foo.cc:23:21: warning: variable 'z2' set but not used [-Wunused-but-set-variable]
  int x1,y1,z1,x2,y2,z2;
                     ^~
/in/foo.cc:27:24: warning: 'y2' may be used uninitialized in this function [-Wmaybe-uninitialized]
   sum[i]=Abs(x1-x2)+Abs(y1-y2);
                     ~~~^~~~~~~
/in/foo.cc:27:13: warning: 'x2' may be used uninitialized in this function [-Wmaybe-uninitialized]
   sum[i]=Abs(x1-x2)+Abs(y1-y2);
          ~~~^~~~~~~