RSA en c++ : tentative

#include <iostream>
#include <string>
#include <cmath>
#include <stdio.h>
#include <math.h>

using namespace std;

int main()
{

unsigned long long int p; unsigned long long int F; unsigned long long int d=1; unsigned long long int k;
unsigned long long int q; unsigned long long int T; unsigned long long int M; unsigned long long int G; long double h;
double n; unsigned long long int e=1; long double c; long double w; long double y;

cout << "P et Q deux nombres premiers" << endl;
cout << "P= ";
cin >> p;
cout << "Q= ";
cin >> q;

n=q*p;
cout << "n= " << n << endl;

F=((p-1)*(q-1));
cout << "F= " << F << endl;

do
{
    e = e + 1;
    if (F % e == 1)
    {
        break;
    }

} while (e < F);
cout << "e= " << e << endl;

do
{
    d = d + 1;

} while (((e*d)%F) != 1);
cout << "d= " << d << endl;

cout << endl;

cout << "Cle publique: (" << n << ";" << e << ")" << endl;
cout << "Cle privee: (" << n << ";" << d << ")" << endl;

cout << endl;

cout << "TEST:" << endl;
cout << "Codage " << endl;
cin >> M;
c=pow(M,e);
if (c >= n)
{
    c=(fmod(c,n));

}
cout << "Se crypte en: " << c << endl;

cout << endl;

cout << "Decodage " << endl;
cin >> G;
h=pow(G,d);
if (h>=n)
{
    h=(fmod(h,n));

}

cout << "Se decrypte en: " << h << endl;
}