其实不必那么麻烦的
```c
#include <bits/stdc++.h>
using namespace std;
int main(){
// freopen("isbn.in", "r", stdin);
// freopen("isbn.out", "w", stdout);
int n,s;
cin>>n;
while(n) s=s*10+n%10,n/=10;
cout<<s;
//fclose(stdin);
//fclose(stdout);
return 0;
}
```
by AceKnightPuppet @ 2023-10-10 20:05:43
建议把s赋值成0
by tyl100908 @ 2023-10-14 14:47:22