如果/ Else / Switch返回错误结果 [英] If / Else / Switch returning the wrong results

问题描述

我正在使用ReactJS制作岩石剪刀布-蜥蜴-史波克（Big Bang Theory，电视节目），而且我遇到某种抽象问题。

I'm making a Rock-Paper-Scissors-Lizard-Spock (Big Bang Theory, the tv show) using ReactJS and i'm facing some kind of abstract issue.

switch (this.state.playerOnePick === 'Rock') {
    case((this.state.playerTwoPick === 'Scissors') || (this.state.playerTwoPick === 'Lizard')):
    return (
        <div>
            <h1>Player One wins !</h1>
            <h2>P1: {this.state.playerOnePick} P2: {this.state.playerTwoPick}</h2>
        </div>
    );
        break;
    case((this.state.playerTwoPick === 'Paper') || (this.state.playerTwoPick === 'Spock')):
        return (
            <div>
                <h1>Player Two wins !</h1>
                <h2>P1: {this.state.playerOnePick}
                    P2: {this.state.playerTwoPick}</h2>
            </div>
        );
        break;

}

switch (this.state.playerOnePick === 'Lizard') {
    case((this.state.playerTwoPick === 'Spock') || (this.state.playerTwoPick === 'Paper')):
        return (
            <div>
                <h1>Player One wins !</h1>
                <h2>P1: {this.state.playerOnePick} P2: {this.state.playerTwoPick}</h2>
            </div>

        );
        break;
    case((this.state.playerTwoPick === 'Scissors') || (this.state.playerTwoPick === 'Rock')):
        return (
            <div>
                <h1>Player Two wins !</h1>
                <h2>P1: {this.state.playerOnePick} P2: {this.state.playerTwoPick}</h2>
            </div>
        );
        break;

}

Rock vs Paper返回正确的结果，无论谁选择它，当P1：岩石，P2：蜥蜴，P1获胜时，但是当P1：蜥蜴P2：岩石，则返回P1获胜。.

Rock vs Paper is returning the right results, no matter who's picking it, when P1: Rock, P2: Lizard, P1 wins as expected, but when P1: Lizard P2: Rock, it is returning that P1 wins..

< a href = https://i.stack.imgur.com/80As0.png rel = nofollow noreferrer>当P1：蜥蜴P2：岩石

在任何地方，蜥蜴人都不应该赢得对岩石的胜利。

There is nowhere where Lizard is supposed to win vs Rock...

（玩家选择武器时，playerOnePick和playerTwoPick会正确更新）

(playerOnePick and playerTwoPick are correctly updated as the player pick a weapon)

推荐答案

switch 语句的正确用法是

switch (this.state.playerOnePick) {
    case 'Rock':
        switch (this.state.playerTwoPick) {
            case 'Scissors'):
            case 'Lizard':
                return "Player One wins!";
                break; // unnecessary after `return` but well
            case 'Paper':
            case 'Spock':
                return "Player Two wins!";
                break; // as above
        }
        break;
    case 'Lizard':
        switch (this.state.playerTwoPick) {
            case 'Spock':
            case 'Paper':
                return "Player One wins!"
            case 'Scissors':
            case 'Rock':
                return "Player Two wins!";
        }
        break;
}

显示的是 if / else ，其中包含许多布尔条件：

What you have shown is the layout for if/else, with lots of boolean conditions:

if (this.state.playerOnePick === 'Rock') {
    if ((this.state.playerTwoPick === 'Scissors') || (this.state.playerTwoPick === 'Lizard')) {
        return "Player One wins!";
    } else if ((this.state.playerTwoPick === 'Paper') || (this.state.playerTwoPick === 'Spock')) {
        return "Player Two wins!";
    }
} else if (this.state.playerOnePick === 'Lizard') {
    if ((this.state.playerTwoPick === 'Spock') || (this.state.playerTwoPick === 'Paper')) {
        return "Player One wins!";
    } else if ((this.state.playerTwoPick === 'Scissors') || (this.state.playerTwoPick === 'Rock')) {
        return "Player Two wins!";
    }
}

但是，实施Rock-Paper的真正问题是Scissors-Lizard-Spock就是所有重复项（这给错误留下了很大的空间）。实际的编程任务是弄清楚如何减少它。

提示：为每个可能的选择分配一个整数，然后进行一些数学运算。

编写一个单独的函数 winner（pick1，pick2）当第一个玩家获胜时返回 -1 ， 0 并列，第二名玩家获胜时， 1 。然后只需从与UI有关的ReactJS代码中调用它即可。

However, the real issue with implementing Rock-Paper-Scissors-Lizard-Spock is all that duplication (which leaves a lot room for error). The actual programming task is to figure out how to reduce that.
Tip: Assign each possible pick an integer number, and play around with some maths.
Write a separate function winner(pick1, pick2) that returns -1 when the first player wins, 0 for a tie, and 1 when the second player wins. Then simply call that from the ReactJS code that is concerned with the UI stuff.

这篇关于如果/ Else / Switch返回错误结果的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！