multiplique strings

#include <iostream>
#include <string>
using namespace std;

string adding(string, string);
string multiplique(string, string);
string subtracting(string, string);
string remove_zeroes(string);
string str_reverse(string);

string str_reverse(string a)
{
    string b;
    for(int i = a.length()-1; i >= 0; i--)
        b += a[i];
    return  b;
}

string remove_zeroes(string a)
{
    string b;
    int length = a.length();
    int n_zero_pos = length;
    for(int i = 0; i < length; i++)
        if(a[i] != '0')
        {
            n_zero_pos = i;
            break;
        }
    if(n_zero_pos == length) return "0";

    for(int i = n_zero_pos; i < length; i++)
        b += a[i];
    return b;
}

int main()
{
    cout << multiplique("62345674563456745674356788456734567834567845678456783456734567834567345673456784567", "96545") << endl;
    return 0;

}

string adding(string a, string b)
{
    int length = max(a.length(), b.length());
    a = str_reverse(a);
    b = str_reverse(b);
    if(a.length() != b.length())
        ((a.length() > b.length()) ? (b) : (a)).resize(length, '0');
    string c;
    c.resize(length + 1);

    for(int i = 0; i < length; i++)
        c[i] = a[i] - '0' + b[i];

    for(int i = 0; i < length; i++)
        if(c[i] > '9')
        {
            c[i] -= 10;
            c[i+1]++;
        }
    c[length] += '0';
    return remove_zeroes(str_reverse(c));
}

string subtracting(string a, string b)
{
    int length = max(a.length(), b.length());
    a = str_reverse(a);
    b = str_reverse(b);
    if(a.length() != b.length())
        ((a.length() > b.length()) ? (b) : (a)).resize(length, '0');
    string c;
    c.resize(length);

    for(int i = 0; i < length; i++)
        c[i] = a[i] + '0' - b[i];

    for(int i = 0; i < length; i++)
        if(c[i] < '0')
        {
            c[i] += 10;
            c[i+1]--;
        }
    return remove_zeroes(str_reverse(c));
}

string multiplique(string a, string b)
{
    string w = a;
    while(subtracting(b, "1") != "0")
    {
        b = subtracting(b, "1");
        w = adding(w, a);
    }
    return w;
}