/in/foo.cc: In function 'int zhishu(int)':
/in/foo.cc:7:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(int i=2;i<x/2;i++)
  ^~~
/in/foo.cc:9:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
   return 1;
   ^~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:63:5: error: 'j' was not declared in this scope
  if(j==30) cout<<"impossible!";
     ^