Any length number multiplier [Selise]

#include <bits/stdc++.h>

using namespace std;

string the_multiplier(string num1, string num2)
{
    string result[num2.size()], final_result = "";
    //the multiplication
    for(int i = 0; i < num2.size(); i++)
    {
        int carry = 0;
        for(int j = 0; j < num1.size(); j++)
        {
            int mul = (num2[i] - '0') * (num1[j] - '0');
            mul += carry;
            carry = mul / 10;
            mul = mul % 10;
            result[i] += mul + '0';
        }
        if(carry) result[i] += carry + '0';
        reverse(result[i].begin(), result[i].end());
        result[i].insert(0, num2.size() - 1 - i, '0');
        for(int k = 0; k < i; k++)
        {
            result[i] += "0";
        }
    }
    int carry = 0, siz = result[0].size() - 1;
    for(int i = siz, sum = 0; i >= 0; i--)
    {
        sum = 0;
        for(int j = 0; j < num2.size(); j++)
        {
            sum += result[j][i] - '0';
        }
        sum += carry;
        carry = sum / 10;
        sum = sum % 10;
        final_result += sum + '0';
    }
    if(carry) final_result += carry + '0';
    reverse(final_result.begin(), final_result.end());
    return final_result;
}

int main()
{
    string num1 = "34523423", num2 = "777";
    if(num1.size() <= num2.size()) swap (num1, num2);
    reverse(num1.begin(), num1.end());
    reverse(num2.begin(), num2.end());
    cout << the_multiplier(num1, num2);
    return 0;
}