foo.cc: In function ‘int main()’:
foo.cc:11:21: warning: unused variable ‘x1’ [-Wunused-variable]
   11 |                 int x1=x%10; //取个位
      |                     ^~
foo.cc:18:17: warning: this ‘if’ clause does not guard... [-Wmisleading-indentation]
   18 |                 if(x%y==0)
      |                 ^~
foo.cc:20:25: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the ‘if’
   20 |                         y++;
      |                         ^