求助,不能输入

#include <bits/stdc++.h>
using namespace std;

int main()
{
    char s1[2005],s2[2005];
    int n1[2005]={},n2[2005]={},ans[2000005]={};
    cin >> s1 >> s2;
    int ls1=strlen(s1),ls2=strlen(s2),la=0;

    //初始化int数组
    for (int i = 0; i < ls1; i++)
        n1[ls1 - i - 1] = s1[i] - '0';
    for (int i = 0; i < ls2; i++)
        n2[ls2 - i - 1] = s2[i] - '0';

    //计算乘法
    la = max(ls1,ls2);
    for (int i = 0; i < ls1; i++)
    {
        for (int j = 0; j < ls2; j++)
        {
            ans[i] += n1[i] * n2[j];
            ans[i+1] += ans[i] / 10;
            ans[i] %= 10;
        }
    }
    while (ans[la])
        la++;

    for (int i = la-1; i >= 0; i--)
    {
        cout << ans[i];
    }

    return 0;
}