c_cpp 乘以一位数

Posted 2021-05-14

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

multiply (string s, char k) {
    int num, carry = 0;
    stack <char> res;
    for (int i=s.length()-1; i>=0;i--) {
        num = carry + (s[i]-'0')*(k- '0');
        carry = num/10;
        res.push(num%10+ '0');
        if (i==0 && num/10>0)
            res.push(num/10 + '0');
    }
    s.clear();
    while (!res.empty()) {
        s+=res.top();
        res.pop();
    }
    cout<< s;
}

int main() {
    string s;
    char k;
    getline(cin, s);
    cin>>k;

    multiply (s, k);
}