[C++] vprašanja

C++ pozna samo naravni logaritem in logaritem z bazo 10.

#include <cmath>
template <double N, class T>
T logn(T num) {
   if (N == 0) return 0;
   return (T)(std::log(num) / std::log(N));
}

int M = 95;
for (int i=1; i<23; ++i) {
   M = (M * M) % 187;
}

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

int main()
{
/*Prvo izberete dve prastevili p in q;
{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 53, 59, 61, 67, 71, 73, 79, 
83, 89, 97, 101} - Tabela prastevil do 101;
*/
  int p;
  int q;
  int N;

  char znak;

  int M;
  int C;
  int e;
/*S paroma stevil e in N naredite svoj javni kljuc
Zasebni kljuc pa dobimo tako : e * d = 1 mod N (e in N - poznamo iz javnega kljuca);
Z uporabo evklidovega algoritma lahko izracunamo d;
Ko imamo C(zakodirana crka), d in N potem 
po formuli M = C^d(modN) dobimo crko katro smo zakodirali
*/
  cout << "Vnesi p    : "; 
  cin >> p;
  cout << "Vnesi q    : "; 
  cin >> q;
  N = p * q;
  cout << "p * q = N  : " << N << endl;
  cout << "Vnesi e    : "; 
  cin >> e;
   
  do
  {
    cout << "Vnesi znak : "; 
    cin >> znak;
    M = znak;
    cout << "ASCII koda : " << M << endl;
    C = M * M; 
    for (int i= 1; i < (e-1) ; ++i) 
    {
     C = (C * M) % N;
    }
    cout << "C          : " << C << endl
         << "Novi znak  : " << (znak = C) << endl 
         << "-------------------" << endl;
  }
  while (znak != 'Đ'); //Đ ne uporablja SSKJ 
return 0;
}

Kaj pa C++ ima prav funkcijo za Evklidov algoritem ali jo moram sam narediti ?

Prosil bi če sem napisal čisti C++ v prešnji kodi.

#include <iostream.h>
#include <stdlib.h>

int main()
{
      int a, b, o = 1;

      cout << "Vpišite število a in b(med števili naredite presledek):";
      cin >> a >> b;

      while (o != 0)
            {
             o = a % b;
             a = b;
             b = o;
            }
      cout << "Največji skupni deljitelj števel je: " << a << endl;

      system("PAUSE");
      return 0;
}

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

bool Evklid(int e, int N)
{
  int o = 1;
  while (o != 0)
  { 
    o = N % e;
    N = e;
    e = o;
  }
  if (N == 1) return true;
  if (N != 1) return false;
}
//glavni program 
int main()
{
  int p, q, N, d, M, C, e, PomSpre;
  char znak;
  bool yes_no = false;
  do 
  {
    cout << "Vnesi p....: "; 
    cin >> p;
    cout << "Vnesi q....: "; 
    cin >> q;
    cout << "Vnesi e....: ";
    cin >> e;
    yes_no = Evklid(e,((p - 1)*(q - 1)));
    if (yes_no != true)
      cout << "Najvecji skupni deljitelj ni enak 1!" << endl
           << "Isci novega!" << endl;
    else 
      d = ((p-1)*(q-1)+1) / e;
  }while(yes_no !=  true);
  cout << "Zasebni kljuc -> (" << p << " , " << q << ")" << endl;
  cout << "Javni kljuc -> (" << e << " , " << p*q << ")" << endl << endl;
  
  do
  { 
    cout << "Vnesi znak.: "; 
    cin >> znak;
    M = znak;
//uporabljena formula C = M ^ e (mod N)
    N = p * q; 
    C = 1; 
    for (int y = 1; y <= e ; ++y)
    {
      C = (C * M) % N;
      cout << C << " = " << M << "^" << y << endl; 
    }
    cout << endl
         << "M..........: " << M << endl
         << "----------------" << endl;
         M = 0; //zaradi preverjanja drugače bo to ločeno
//uporabljena formula M = C ^ (mod N);
      M = 1;
      for (int x = 1; x <= d; ++x)
      {
	M = (M * C) % N;
        cout << M << " = " << C << "^" << x << endl;
      }
    cout << "M..........: " << M << endl
         << "----------------" << endl;
  }
  while (znak != 'Đ'); //Đ ne uporablja SSKJ
return 0;
}