`luc030.c`¶

Problem Statement

Write a program for a matchstick game being played between the computer and a user. Your program should ensure that the computer always wins. Rules for the game are as follows : - There are 21 matchsticks. - The computer asks the player to pick 1, 2, 3, or 4 matchsticks. - After the person picks, the computer does its picking. - Whoever is forced to pick up the last matchstick loses the game.

Metadata¶

Property	Detail
Author	Amit Dutta amitdutta4255@gmail.com
Date	12 Dec 2025
License	MIT License (See the LICENSE file for details)
Difficulty	Beginner (index: 2 / 10)

Concepts¶

Beta Feature

This concept detection system is still in beta and may occasionally show incorrect or incomplete results.

Iteration

Actions¶

Raw View on GitHub

You can print or save this file by opening Raw and using your browser.

Source Code¶

#include <stdio.h>
int main()
{
    int remaining_matchsticks = 21, player_pick, computer_pick;
    printf("                 --- Matchstick Game ---\n");
    printf("Rules: There are 21 matchsticks. You can pick 1, 2, 3, or 4.\n");
    printf("Whoever is forced to pick the last matchstick loses the game.\n");
    while (remaining_matchsticks > 1)
    {
        // game start
        printf("\n--------------------------");
        printf("\nRemaining Matchsticks : %d", remaining_matchsticks);

        // player pick and checking input is valid or not
        printf("\nYour turn: Pick 1, 2, 3, or 4 matchsticks: ");
        if (scanf("%d", &player_pick) != 1)
        {
            printf("\n\tPlease enter a number.");
            while (getchar() != '\n')
                ;
            continue;
        }

        // checking player pick is valid or not
        if (player_pick < 1 || player_pick > 4)
        {
            printf("\n\tPlease enter a number among 1, 2, 3 and 4.");
            while (getchar() != '\n')
                ;
            continue;
        }

        if (player_pick > remaining_matchsticks)
        {
            printf("\nInvalid choice! There are not enough matchsticks left.");
            while (getchar() != '\n')
                ;
            continue;
        }

        // computer_picks
        computer_pick = 5 - player_pick;
        printf("\ncomputer_picks : %d", computer_pick);

        // remaining matchsticks
        remaining_matchsticks = remaining_matchsticks - (player_pick + computer_pick);
    }

    // game over
    printf("\n----------------------------------\n");
    printf("Only 1 matchstick is left.\n");
    printf("You are forced to pick the last matchstick. You lose!\n");
    printf("The computer wins.\n");

    return 0;
}

Explanation¶

Explain with AI

Copy the prompt below and paste it into any AI assistant.

    You are explaining a C programming code to a beginner.

    STRICT RULES:

    - Only use the given code. Do NOT assume anything not present.

    - Do NOT add extra examples.

    - Keep explanation clear and short.

    - If something is unclear, say "Not clear from code".

    - Follow the exact format below. Do NOT change headings.

    FORMAT:

    [START]

    ## What it does

    (Explain the overall purpose in 1-2 sentences)

    ## Step-by-step

    (Explain how the code works in steps, simple language)

    ## Key Concepts

    (List concepts like loop, condition, function, etc.)

    ## Notes

    (Mention any limitations, errors, or assumptions)

    [END]

    CODE (luc030.c):

    #include <stdio.h>
    int main()
    {
        int remaining_matchsticks = 21, player_pick, computer_pick;
        printf("                 --- Matchstick Game ---\n");
        printf("Rules: There are 21 matchsticks. You can pick 1, 2, 3, or 4.\n");
        printf("Whoever is forced to pick the last matchstick loses the game.\n");
        while (remaining_matchsticks > 1)
        {
            // game start
            printf("\n--------------------------");
            printf("\nRemaining Matchsticks : %d", remaining_matchsticks);

            // player pick and checking input is valid or not
            printf("\nYour turn: Pick 1, 2, 3, or 4 matchsticks: ");
            if (scanf("%d", &player_pick) != 1)
            {
                printf("\n\tPlease enter a number.");
                while (getchar() != '\n')
                    ;
                continue;
            }

            // checking player pick is valid or not
            if (player_pick < 1 || player_pick > 4)
            {
                printf("\n\tPlease enter a number among 1, 2, 3 and 4.");
                while (getchar() != '\n')
                    ;
                continue;
            }

            if (player_pick > remaining_matchsticks)
            {
                printf("\nInvalid choice! There are not enough matchsticks left.");
                while (getchar() != '\n')
                    ;
                continue;
            }

            // computer_picks
            computer_pick = 5 - player_pick;
            printf("\ncomputer_picks : %d", computer_pick);

            // remaining matchsticks
            remaining_matchsticks = remaining_matchsticks - (player_pick + computer_pick);
        }

        // game over
        printf("\n----------------------------------\n");
        printf("Only 1 matchstick is left.\n");
        printf("You are forced to pick the last matchstick. You lose!\n");
        printf("The computer wins.\n");

        return 0;
    }

luc030.c¶