C++ 高精度除法

#include 
#include 
#include 
#include 

using namespace std;

vector div(vector &A, int b, int &r)
{
    vector C;
    
    r = 0;
    for ( int i = A.size() - 1; i >= 0; i-- )
    {
        r = r * 10 + A[i];
        C.push_back( r / b );
        r %= b;
    }
    reverse(C.begin(), C.end());
    while ( C.size() > 1 && C.back() == 0 ) C.pop_back();
    return C;
}

int main()
{
    string a;
    int b;
    vector A;
    
    cin >> a >> b;
    for ( int i = a.size() - 1; i >= 0; i-- ) A.push_back(a[i] - '0');
    
    int r;
    vector C = div(A, b, r);
    
    for ( int i = C.size() - 1; i >= 0; i-- ) cout << C[i];
    cout << endl << r << endl;
    
    return 0;
}