Rock, paper, scissors

Rock, paper, scissors

The classic game for two.

Rock paper scissors is a hand game originating from China, played between two people, in which each player simultaneously forms one of three shapes with an outstretched hand. These shapes are “rock” (a closed fist), “paper” (a flat hand), and “scissors” (a fist with the index finger and middle finger extended, forming a V).


The rock beats the scissors. The paper beasts the rock and the scissors beats the paper. This version of the game is played between a user and the computer over five rounds. The first player to win five rounds wins the game.

Make


Write a program that simulates the game rock, paper, scissors to be played by the user against the computer.

Use this boilerplate code as a starting point:

Success Criteria

Remember to add a comment before a subprogram, selection or iteration statement to explain its purpose.

Create a subprogram called `get_player_choice` that:

  1. Asks the user to enter their choice of rock, paper or scissors as a letter: r, p or s.
  2. Returns the choice only when it is a valid letter.

Create a subprogram called `convert` that:

  1. Takes a string parameter called `rps`.
  2. If rps is “r” it returns “rock”.
  3. If rps is “p” it returns “paper”.
  4. If rps is “s” it returns “scissors”.

This is a helper function that converts a single character input from the user (their choice) into something more readable for output.

Create a subprogram called `cpu_choice` that:

  1. Generates a random number between 1 and 3.
  2. Returns the choice as “r”, “p” or “s” instead of 1, 2 or 3.

Create a subprogram called `who_won_round` that:

  1. Takes two parameters, `player` and `cpu` which are the two choices made: “r”, “p” or “s”.
  2. Determines who won the round.
  3. Returns the winner of the round as “player”, “cpu” or “draw”.

Create a subprogram called `play_game` that:

  1. Plays the game as described using the subprograms above.
  2. Outputs the current score of each player before each round. (Winning a round scores one point.)
  3. Outputs the choice of both players, including who beat whom, or if the round was a draw.
  4. Outputs who won the game after one player reaches five points.

Complete the `main program` so that:

  1. The `play_game` subprogram is called.

Typical inputs and outputs from the program would be:

player score: 0 cpu score: 0

Enter rock, paper, scissors (r/p/s): g

Enter rock, paper, scissors (r/p/s): h

Enter rock, paper, scissors (r/p/s): r

player’s rock beats cpu’s scissors


player score: 1 cpu score: 0

Enter rock, paper, scissors (r/p/s): p

cpu’s scissors beats player’s paper


player score: 1 cpu score: 1

Enter rock, paper, scissors (r/p/s): s

cpu’s rock beats player’s scissors


player score: 1 cpu score: 2

Enter rock, paper, scissors (r/p/s): r

rock – rock – it’s a draw.


player score: 1 cpu score: 2

Enter rock, paper, scissors (r/p/s): p

player’s paper beats cpu’s rock


player score: 2 cpu score: 2

Enter rock, paper, scissors (r/p/s): s

scissors – scissors – it’s a draw.


player score: 2 cpu score: 2

Enter rock, paper, scissors (r/p/s): r

rock – rock – it’s a draw.


player score: 2 cpu score: 2

Enter rock, paper, scissors (r/p/s): p

cpu’s scissors beats player’s paper


player score: 2 cpu score: 3

Enter rock, paper, scissors (r/p/s): s

cpu’s rock beats player’s scissors


player score: 2 cpu score: 4

Enter rock, paper, scissors (r/p/s): r

cpu’s paper beats player’s rock


CPU WINS!

Knowledge Organiser

Use these resources as a reference to help you meet the success criteria.

Programming guide:

Evaluate


Run the program several times to check that your program has met the success criteria.

Check that you have:

  • Used comments within the code to describe the purpose of subprograms, conditions and iterations.
  • Used meaningful identifier names. That means the names of subprograms and variables indicate what they are for.
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