代码

#include <bits/stdc++.h>
using namespace std;
 
int main(int argc, char const *argv[])
{
    string s1, s2;
    int a[250], c[500];
    int m = 0;
    int len1, len2;
    memset(a, 0, sizeof(a) / sizeof(int));
    memset(c, 0, sizeof(c) / sizeof(int));
    cin >> s1;
    cin >> m;
    int len;
    if (s1 == "0" || m == 0)
    {
        cout << "0";
    }
    else
    {
        len = s1.size();
        for (int i = 0; i < len; i++)
        {
            a[i] = s1[len - i - 1] - '0';
        }
    }
 
    for (int i = 0; i < len; i++)
    {
        c[i] = a[i] * m;
    }
 
    for (int i = 0; i < len; i++)
    {
        c[i + 1] = c[i + 1] + c[i] / 10;
        c[i] = c[i] % 10;
    }
 
    while (c[len])
    {
        len++;
        c[len] = c[len - 1] / 10;
        c[len - 1] = c[len - 1] % 10;
    }
 
    for (int i = len - 1; i >= 0; i--)
    {
        cout << c[i];
    }
    return 0;
}