/in/foo.cc: In function 'void Add(int, int)':
/in/foo.cc:159:13: warning: variable 'idx' set but not used [-Wunused-but-set-variable]
  159 |         int idx=0;
      |             ^~~
/in/foo.cc: In function 'void Add1(int, int)':
/in/foo.cc:178:13: warning: variable 'idx' set but not used [-Wunused-but-set-variable]
  178 |         int idx=0;
      |             ^~~
/in/foo.cc: In function 'void Add2(int, int)':
/in/foo.cc:197:13: warning: variable 'idx' set but not used [-Wunused-but-set-variable]
  197 |         int idx=0;
      |             ^~~