OK了呀

#include<bits/stdc++.h>
using namespace std;
int ans[10005];
bool is_ou(int x){
    while(x > 0){
        int yu = x % 10;
        if(yu % 2) return false;
        x /= 10;
    }
    return true;
}
int main(){
    int idx = 1;
    int a,b; cin >> a >> b;
    for(int i = a;i <= b;i++){
        if(is_ou(i)) ans[idx++] = i;
    }
    for(int i = 1;i < idx;i++){
        cout << ans[i];
        if(i != idx - 1) cout << ",";
    }
    return 0;
}