Question

You are asked to implement scissors-rock-paper game where the players are a computer and a user. The player that wins 3 hands successively is the winner of the game. Your program should prompt the user with a message at the beginning of each hand to enter one of scissors, rock or paper. If the user's entry is not valid, i.e. entry is neither scissors, rock, nor paper, your program throws a message to the user to enter a valid entry and waits for that to happen Computer randomly chooses among scissors, rock or paper at each hand Scissors beats paper. Rock defeats scissors and paper whips rock Hint: it is highly recommended to have a modular implementation. Write a function which accepts two arguments one for computer's choice and the other for the user's pick and returns whether computer is winner of the hand or the user. You may also write two functions where one maps scissors, rock or paper to 3 positive integers with respect to an order and the other maps the other way around It is not necessary to follow the approach stated in the hint.

Answer 1

Below is the solution:

code:

#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std;
int computerWin=0,userWin=0;

void playRockPaperScissor(char userChoice, char computerChoice){
   //check here for the computer wins of user win score update when tie there is no score of both
   if((computerChoice == 'r' || computerChoice == 'R') && (userChoice == 'r' || userChoice == 'R'))
   {
       cout << "It was a tie!" << endl;
   }
   else if ((computerChoice == 'p' || computerChoice == 'P') && (userChoice == 'p' || userChoice == 'P'))
   {
        cout << "It was a tie!" << endl;
   }
   else if ((computerChoice == 's' || computerChoice == 'S') && (userChoice == 's' || userChoice == 'S'))
   {
        cout << "It was a tie!" << endl;
   }
   else if ((computerChoice == 'r' || computerChoice == 'R') && (userChoice == 's' || userChoice == 'S'))
   {
        cout << "Computer won!" << endl;
        //userWin--;
        computerWin++;
   }
   else if ((computerChoice == 'p' || computerChoice == 'P') && (userChoice == 'r' || userChoice == 'R'))
   {
       //userWin--;
        computerWin++;
        cout << "Computer won!" << endl;
   }
   else if ((computerChoice == 's' || computerChoice == 'S') && (userChoice == 'p' || userChoice == 'P'))
   {
        cout << "Computer won!" << endl;
        //userWin--;
        computerWin++;
   } else {
        cout << "You won!" << endl;
        userWin++;
        //computerWin--;
   }
}

int main()
{
    char userChoice;
   char computerChoice[]="rps"; //computer choice char array
  
    int r;
    unsigned seed;
  
    do{
          //The choices
        cout << "\n===================\n";
        cout << "R. Rock\n";
        cout << "P. Paper\n";
        cout << "S. Scissors\n";
        cout << "X. Quit the game.\n";
        cout << "===================\n";
        cout << "Please enter your choice::: ";
        cin >> userChoice;
      
         //display the user choice.
        if (userChoice == 'R' || userChoice == 'r') //Rock
        {
            cout << "You picked Rock.\n";
        }
      
        else if (userChoice == 'P' || userChoice == 'p') //Paper
        {
            cout << "You picked Paper.\n";
        }
      
        else if (userChoice == 'S' || userChoice == 's') //Scissors
        {
            cout << "You picked Scissors.\n";
        }
        else if (userChoice == 'x' || userChoice == 'X') //Scissors
        {
            break;
        }else{
           cout<<"Wrong choice!";
           exit(0);
       }
      
      
        //generate random number 1 to 3
        seed = time(0);
        srand(seed); //For the random generator.
          
       r = rand() % 3 + 1; //Computers pick between 1 to 3 for r p s or R P S.
      
      
       //assign the random number to the computer choice char array to check for the r,p,s
       if (computerChoice[r] == 'r') //Rock
        {
            cout<< "Computer picked Rock.\n";
        }
      
        else if (computerChoice[r] == 'p') //Paper
        {
            cout << "Computer picked Paper.\n";
        }
      
        else if (computerChoice[r] == 's') //Scissors
        {
            cout << "Computer picked Scissors.\n";
        }
      
       playRockPaperScissor(userChoice, computerChoice[r]); //method to play Rock Paper Scissor

       //check for the computer win 3 times
       if(computerWin==3){  
           cout << "\n==================================\n";
           cout<<"*\tCongrats! Computer wins.\t*";
           cout << "\n==================================\n";
           break;
       }
       //check for the user win 3 times
       if(userWin==3){
           cout << "\n=================================\n";
           cout<<"*\tCongrats! User wins.\t*";
           cout << "\n=================================\n";
           break;
       }          
   }while(userChoice != 'x' || userChoice != 'X');
   system("pause");
   return 0;
}

sample output:

===================
R. Rock
P. Paper
S. Scissors
X. Quit the game.
===================
Please enter your choice::: s
You picked Scissors.
Computer picked Scissors.
It was a tie!

===================
R. Rock
P. Paper
S. Scissors
X. Quit the game.
===================
Please enter your choice::: s
You picked Scissors.
Computer picked Scissors.
It was a tie!

===================
R. Rock
P. Paper
S. Scissors
X. Quit the game.
===================
Please enter your choice::: s
You picked Scissors.
Computer picked Scissors.
It was a tie!

===================
R. Rock
P. Paper
S. Scissors
X. Quit the game.
===================
Please enter your choice::: s
You picked Scissors.
You won!

===================
R. Rock
P. Paper
S. Scissors
X. Quit the game.
===================
Please enter your choice::: p
You picked Paper.
Computer picked Paper.
It was a tie!

===================
R. Rock
P. Paper
S. Scissors
X. Quit the game.
===================
Please enter your choice::: r
You picked Rock.
Computer picked Paper.
Computer won!

===================
R. Rock
P. Paper
S. Scissors
X. Quit the game.
===================
Please enter your choice::: s
You picked Scissors.
Computer picked Paper.
You won!

===================
R. Rock
P. Paper
S. Scissors
X. Quit the game.
===================
Please enter your choice::: r
You picked Rock.
Computer picked Scissors.
You won!

=================================
*       Congrats! User wins.    *
=================================