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

void playGame();
int genRandNum();
string userChooses();
bool playAgain();

bool playAgain() {
	string stayOrGo;
	do {
		cout << "\nType 'y' to play again, 'n' to quit.\n" << endl;
		cin >> stayOrGo;
		if (stayOrGo != "y" && stayOrGo != "n") {
			cout << "\nThat is not correct input." << endl;
		}
	} while (stayOrGo != "y" && stayOrGo != "n");
	
	return stayOrGo == "y";
}

int genRandNum() {
	int randomNumber;
	srand(time(0));
	randomNumber = rand() % 3 + 1;
	return randomNumber;
}

string userChooses() {
	string userChoice;
	do {
		cout << "\nDo you choose 'rock', 'paper' or 'scissors'?\n\n";
		cin >> userChoice;
		if (userChoice != "rock"
			&& userChoice != "paper"
			&& userChoice != "scissors") {
			cout << "\nThat is not correct input." << endl;
		}
	} while (userChoice != "rock"
		&& userChoice != "paper"
		&& userChoice != "scissors");
	cout << "\nYou have chosen: " << userChoice << endl;
	return userChoice;
}

string computerChooses(int randomNumber) {
	string computerChoice;
	if (randomNumber == 1) {
		computerChoice = "rock";
		cout << "\nThe computer has chosen: " << computerChoice << endl;
	}
	else if (randomNumber == 2) {
		computerChoice = "paper";
		cout << "\nThe computer has chosen: " << computerChoice << endl;
	}
	else {
		computerChoice = "scissors";
		cout << "\nThe computer has chosen: " << computerChoice << endl;
	}
	return computerChoice;
}

void compareChoices(string userChoice, string computerChoice) {
	// If userChoice is rock
	if (userChoice == "rock") {
		if (computerChoice == "paper") {
			cout << "\nPaper beats rock, you lose!" << endl;
		} else if(computerChoice == "scissors") {
			cout << "\nRock beats scissors, you win!" << endl;
		}
		else {
			cout << "\nIt's a tie!" << endl;
		}
	}
	// If userChoice is paper
	if (userChoice == "paper") {
		if (computerChoice == "scissors") {
			cout << "\nScissors beats paper, you lose!" << endl;
		}
		else if (computerChoice == "rock") {
			cout << "\nPaper beats rock, you win!" << endl;
		}
		else {
			cout << "\nIt's a tie!" << endl;
		}
	}
	// If userChoice is scissors
	if (userChoice == "scissors") {
		if (computerChoice == "rock") {
			cout << "\nRock beats scissors, you lose!" << endl;
		}
		else if (computerChoice == "paper") {
			cout << "\nScissors beats paper, you win!" << endl;
		}
		else {
			cout << "\nIt's a tie!" << endl;
		}
	}
}

void playGame() {
	string userChoice = userChooses();
	string computerChoice = computerChooses(genRandNum());
	compareChoices(userChoice, computerChoice);
}

int main() {
	do {
		playGame();
	} while (playAgain());
	cout << "\nYou have chosen to exit the game.\n" << endl;
	system("PAUSE");
	return 0;
}