c语言编程实现 21根火柴游戏。现有21根火柴，两人轮流取，每人每次可以取1至4根，不可多取（假如多取或者取走的数量不在合法的范围内，则要求重新输入），也不能不取，谁取最后一根火柴谁输。请编写一个程序进行人机对弈，要求人先取，计算机后取；请设计一种计算机取走火柴的规则，使得计算机一方为常胜将军。 **输入格式要求："%d" 提示信息："Game begin:\n" "How many sticks do you wish to take (1~%d)?" **输出格式要求：" %d sticks left in the pile.\n" " You have taken the last sticks.\n" " ***You lose!\nGame Over.\n" "Computer take %d sticks.\n" 程序运行示例如下： Game begin: How many sticks do you wish to take (1~4)?6 How many sticks do you wish to take (1~4)?3 18 sticks left in the pile. Computer take 2 sticks. 16 sticks left in the pile. How many sticks do you wish to take (1~4)?3 13 sticks left in the pile. Computer take 2 sticks. 11 sticks left in the pile. How many sticks do you wish to take (1~4)?3 8 sticks left in the pile. Computer take 2 sticks. 6 sticks left in the pile. How many sticks do you wish to take (1~4)?3 3 sticks left in the pile. Computer take 2 sticks. 1 sticks left in the pile. How many sticks do you wish to take (1~1)?2 How many sticks do you wish to take (1~1)?1 You have taken the last sticks. ***You lose! Game Over.

好的，这是一个比较经典的小游戏，我可以用C语言帮您实现。以下是代码实现：

#include <stdio.h>

int main() {
    int sticks = 21; // 初始火柴数
    int take, computerTake; // 玩家和计算机取的火柴数
    printf("Game begin:\n");
    while (sticks > 0) {
        printf("%d sticks left in the pile.\n", sticks);
        printf("How many sticks do you wish to take (1~4)? ");
        scanf("%d", &take);
        while (take < 1 || take > 4 || take > sticks) {
            printf("Illegal move. Please try again.\n");
            printf("How many sticks do you wish to take (1~4)? ");
            scanf("%d", &take);
        }
        sticks -= take;
        if (sticks == 0) {
            printf("%d sticks left in the pile.\n", sticks);
            printf("You have taken the last sticks.\n");
            printf("***You lose!\nGame Over.\n");
            break;
        }
        computerTake = (5 - take) % 5;
        printf("%d sticks left in the pile.\n", sticks);
        printf("Computer take %d sticks.\n", computerTake);
        sticks -= computerTake;
        if (sticks == 0) {
            printf("%d sticks left in the pile.\n", sticks);
            printf("Computer has taken the last sticks.\n");
            printf("***You win!\nGame Over.\n");
            break;
        }
    }
    return 0;
}

程序中，我们使用了一个 while 循环，不断进行玩家和计算机的取火柴操作，直到火柴数量为 0。每次玩家取火柴前，都会判断其取的火柴数量是否合法，不合法则要求重新输入。而计算机则根据玩家取的火柴数量，采用一定的策略来取火柴。这里，我们使用了一个简单的策略：让计算机取的火柴数量加上玩家取的火柴数量等于 5。这样，计算机就可以在保证不输的前提下，尽可能地拖延游戏进程，增加玩家输的可能性。

运行程序后，可以按照提示进行游戏。如果您想让计算机更聪明一些，可以尝试采用其他的策略，比如根据当前剩余的火柴数和玩家的取火柴数量，来决定计算机应该取多少火柴。