/in/foo.cc: In function 'int main()':
/in/foo.cc:5:8: warning: unused variable 'i' [-Wunused-variable]
  int n,i,j;
        ^
/in/foo.cc:5:10: warning: unused variable 'j' [-Wunused-variable]
  int n,i,j;
          ^
/in/foo.cc:7:10: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized]
  for(int i=i;i<=n;i++)
          ^