luc030.c

Metadata

• Author — Amit Dutta
• Last updated — 12 Dec 2025
• License — MIT License (See the LICENSE file for details)

Problem Statement

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.

Source Code

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#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;
}