foo.cc: In function 'int main()':
foo.cc:13:22: warning: unused variable 'i1' [-Wunused-variable]
  int m,n,a[100][100],i1=0,j1=0,x=1;
                      ^~
foo.cc:13:27: warning: unused variable 'j1' [-Wunused-variable]
  int m,n,a[100][100],i1=0,j1=0,x=1;
                           ^~
foo.cc:13:32: warning: unused variable 'x' [-Wunused-variable]
  int m,n,a[100][100],i1=0,j1=0,x=1;
                                ^

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。