/in/foo.cc: In function 'void cheng(voctor, voctor, voctor, int)':
/in/foo.cc:22:9: warning: variable 'x1' set but not used [-Wunused-but-set-variable]
   22 |     int x1,y1,z1;
      |         ^~
/in/foo.cc:22:12: warning: variable 'y1' set but not used [-Wunused-but-set-variable]
   22 |     int x1,y1,z1;
      |            ^~
/in/foo.cc:22:15: warning: variable 'z1' set but not used [-Wunused-but-set-variable]
   22 |     int x1,y1,z1;
      |               ^~