题解

#include <bits/stdc++.h>
using namespace std;
int main(){
    int a ,b ,x ,sum = 0;
    cin >> a >> b;
    for (int i = a ; i <= b ; i++){
    	x = i;
        while (x){  //sum加上x的各数位之和
            sum += x % 10;
            x /= 10;
        }
    }
    cout << sum;
    return 0;
}