【POJ】Cow Multiplication（水题）

#include<iostream>
#include<cmath>
#include<cstring>
using namespace std;
typedef long long ll;
const int inf = 0x3f3f3f3f;
int main()
{

    char a[20], b[20];
    cin >> a >> b;
    int i, j, sum = 0, la, lb;
    la = strlen(a);
    lb = strlen(b);
    for(i = 0; i < la; i++)
    {
        for(j = 0; j < lb; j++)
        {
            sum += ((a[i] - ‘0‘) * (b[j] - ‘0‘));
        }
    }
    cout << sum << endl;


    return 0;
}