War Card Game Randomizer

[koreanpanda18]

Hello everyone, I recently made a simplified version of the card game War. However when I run the program, I get proper scores outputs but the results do not change between games.
For example, I can run the game 2 or 3 times and all the results would be the same. I think there is a problem with my deck shuffle equation but I'm at a loss to where it is. Thanks for the help!

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

using namespace std;

enum suits {spade, heart, club, diamond};

class card {
public:
	card ();
	card (suits, int);

	int rank;
	suits suit;
};

card::card (){
	rank = 1;
	suit = spade;
}

card::card (suits sv, int rv){
	rank = rv;
	suit = sv;
}

ostream & operator << (ostream & out, card & select){
	switch (select.rank){
		case 1:
			cout << "Ace";
			break;
		case 11:
			cout << "Jack";
			break;
		case 12:
			cout << "Queen";
			break;
		case 13:
			cout << "King";
			break;
		default:
			cout << select.rank;
			break;
	}
	switch (select.suit){
		case spade:
			cout << " of Spades";
			break;
		case heart:
			cout << " of Hearts";
			break;
		case club:
			cout << " of Clubs";
			break;
		case diamond:
			cout << " of Diamonds";
			break;
		}
	return out;
}

class randomint {
	public:
		unsigned int operator () (unsigned int);
} randomizer;

unsigned int randomint::operator () (unsigned int max){
	unsigned int rval = rand();
	return rval % max;
}

class deck {
public:
	deck();
	void shuffle(){
		random_shuffle (cards, cards+52, randomizer);
	}
	bool isempty(){
		return topcard <= 0;
	}
	card draw();
protected:
	card cards[52];
	int topcard;
};

deck::deck (){
	topcard = 0;
	for (int i = 1; i <= 13; i++){
		card c1(spade, i), c2(heart, i), c3(club, i), c4(diamond, i);
		cards[topcard++] = c1;
		cards[topcard++] = c2;
		cards[topcard++] = c3;
		cards[topcard++] = c4;
	}
}

card deck::draw(){
	if (! isempty()){
		return cards[--topcard];
	}
	else {
		card spadeace(spade, 1);
		return spadeace;
	}
}

class player{
public:
	player (deck &);

	card draw();
	void addpoints(int);
	int score();
	void replacecard(deck &);
protected:
	card mycards[3];
	int myscore;
	int removedcard;
};

player::player (deck & adeck){
	myscore = 0;
	for (int i = 0; i < 3; i++){
		mycards[i] = adeck.draw();
	}
	removedcard = 0;
}

card player::draw(){
	removedcard = randomizer(3);
	return mycards[removedcard];
}

void player::addpoints(int howmany){
	myscore += howmany;
}

int player::score (){
	return myscore;
}

void player::replacecard(deck & adeck){
	mycards[removedcard] = adeck.draw();
}

int main(){
	deck thedeck;
	thedeck.shuffle();

	player player1(thedeck);
	player player2(thedeck);

	while (! thedeck.isempty()){
		card card1 = player1.draw();
		cout << "Player 1 plays: " << card1 << endl;
		card card2 = player2.draw();
		cout << "Player 2 plays: " << card2 << endl;

		if (card1.rank == card2.rank) {
			player1.addpoints(1);
			player2.addpoints(1);
			cout << "Its a Draw!" << endl;
		}
		else if (card1.rank > card2.rank){
			player1.addpoints(2);
			cout << "Player 1 wins!" << endl;
		}
		else {
			player2.addpoints(2);
			cout << "Player 2 wins!" << endl;
		}
		player1.replacecard(thedeck);
		player2.replacecard(thedeck);
	}

	cout << "Player 1 score: " << player1.score() << endl;
	cout << "Player 2 score: " << player2.score() << endl;
}

[coder777]

You need srand(...) at the top of your main function:

http://www.cplusplus.com/reference/cstdlib/srand/?kw=srand

Use the time(...) function as shown in that example.

[ncomputersorg]

You can try this:

srand(time(0));

Or this (C++11):

#include<random>

void something(){
  random_device rd;
  //Replace rand() with:
  rd();
}

The problem is that the rand() method is a pseudorandom number generator. The numbers seem to be random, but they are not random. There is always a seed, hence predictable.

If your computer doesn't have a random hardware device, also the random_device implementaion will generate pseudo random numbers. You can check it with:

rd.entropy();

With pseudo random numbers generator the entropy remains unchanged.

For true random numbers you can try to adapt these codes:

http://ncomputers.org/projects/random

But I think that the srand() or random_device options will work pretty well for this case.