我的 switch 语句格式是否错误？

发布于 2024-10-31 13:37:28 字数 3504 浏览 0 评论 0原文

我一直在做一个“剪刀石头布”游戏，看看我是否了解 JavaScript 的基础知识。一切都运行良好，直到我到达 fight() 中第 30 行到第 71 行的 if 语句：我已经调整了应答变量以指示它如何“if'ing”。它似乎返回整个“if”中每个子“if”的默认值。我是否在次要条件中使用了错误的变量？

radioGroup.html

    <script type = "text/javascript">
      //<![CDATA[
      // from radioGroup.html
      function fight(){
        var randomChoice = Math.random();
        var threeChoice = Math.floor (randomChoice * 3);
        var weapon = document.getElementsByName("weapon");

        for (i = 0; i < weapon.length; i++){
          currentWeapon = weapon[i];

          if (currentWeapon.checked){
            var selectedWeapon = currentWeapon.value;
          } // end if

        } // end for

        var cpuChoice = new Array("Paper", "Rock", "Scissors")
        var reply = "xxx"
        if (threeChoice === 0) {
            if (weapon === "Paper") {
                reply = "11";
                }
            else if (weapon === "Rock") {
                    reply = "12";
                }
            else if (weapon === "Scissors") {
                    reply = "13";
                    }
            else {
                    reply = "what1";
                    }
        }else if (threeChoice === 1) {
                if (weapon === "Paper") {
                reply = "21";
                }
            else if (weapon === "Rock") {
                    reply = "22";
                }
            else if (weapon === "Scissors") {
                    reply = "23";
                    }
            else {
                    reply = "what2";
                    }
        }else if (threeChoice === 2) {
                if (weapon === "Paper") {
                reply = "31";
                }
            else if (weapon === "Rock") {
                    reply = "32";
                }
            else if (weapon === "Scissors") {
                    reply = "33";
                    }
            else {
                    reply = "what3";
                    }
        }else {
            reply = "hay now?";
            }
        var output = document.getElementById("output");
        var response = "<h2>You have chosen ";
        response += selectedWeapon + "<h2>The CPU has chosen ";
        "<\/h2> \n";
        response += cpuChoice[threeChoice] + "<\/h2> \n";
        response += reply + "<\/h2> \n";
        output.innerHTML = response;
     } // end function

      //]]>
    </script>
  </head>

  <body>
    <h1>Choose!</h1>
    <form action = "">
      <fieldset>
        <input type = "radio"
               name = "weapon"
               id = "radPaper"
               value = "Paper"
               checked = "checked" />
        <label for = "radPaper">Paper</label>

        <input type = "radio"
               name = "weapon"
               id = "radRock"
               value = "Rock" />
        <label for = "radRock">Rock</label>

        <input type = "radio"
               name = "weapon"
               id = "radScissors"
               value = "Scissors" />
        <label for = "radScissors">Scissors</label>
        <button type = "button"
                onclick = "fight()">
          fight the dragon
        </button>
      </fieldset>
    </form>
    <div id = "output">

    </div>
  </body>
</html>

原文

I have been working on a "Rock Paper Scissors" game to see if I understand the basics of JavaScript. It all works well until I get to the if statement from lines 30 to 71 in the fight(): I have adjusted the reply variable to indicate how it may be "if'ing" through. It seems to be returning the default value of every sub "if" in the overall "if". Am I using the wrong variable for the secondary condition maybe?

radioGroup.html

    <script type = "text/javascript">
      //<![CDATA[
      // from radioGroup.html
      function fight(){
        var randomChoice = Math.random();
        var threeChoice = Math.floor (randomChoice * 3);
        var weapon = document.getElementsByName("weapon");

        for (i = 0; i < weapon.length; i++){
          currentWeapon = weapon[i];

          if (currentWeapon.checked){
            var selectedWeapon = currentWeapon.value;
          } // end if

        } // end for

        var cpuChoice = new Array("Paper", "Rock", "Scissors")
        var reply = "xxx"
        if (threeChoice === 0) {
            if (weapon === "Paper") {
                reply = "11";
                }
            else if (weapon === "Rock") {
                    reply = "12";
                }
            else if (weapon === "Scissors") {
                    reply = "13";
                    }
            else {
                    reply = "what1";
                    }
        }else if (threeChoice === 1) {
                if (weapon === "Paper") {
                reply = "21";
                }
            else if (weapon === "Rock") {
                    reply = "22";
                }
            else if (weapon === "Scissors") {
                    reply = "23";
                    }
            else {
                    reply = "what2";
                    }
        }else if (threeChoice === 2) {
                if (weapon === "Paper") {
                reply = "31";
                }
            else if (weapon === "Rock") {
                    reply = "32";
                }
            else if (weapon === "Scissors") {
                    reply = "33";
                    }
            else {
                    reply = "what3";
                    }
        }else {
            reply = "hay now?";
            }
        var output = document.getElementById("output");
        var response = "<h2>You have chosen ";
        response += selectedWeapon + "<h2>The CPU has chosen ";
        "<\/h2> \n";
        response += cpuChoice[threeChoice] + "<\/h2> \n";
        response += reply + "<\/h2> \n";
        output.innerHTML = response;
     } // end function

      //]]>
    </script>
  </head>

  <body>
    <h1>Choose!</h1>
    <form action = "">
      <fieldset>
        <input type = "radio"
               name = "weapon"
               id = "radPaper"
               value = "Paper"
               checked = "checked" />
        <label for = "radPaper">Paper</label>

        <input type = "radio"
               name = "weapon"
               id = "radRock"
               value = "Rock" />
        <label for = "radRock">Rock</label>

        <input type = "radio"
               name = "weapon"
               id = "radScissors"
               value = "Scissors" />
        <label for = "radScissors">Scissors</label>
        <button type = "button"
                onclick = "fight()">
          fight the dragon
        </button>
      </fieldset>
    </form>
    <div id = "output">

    </div>
  </body>
</html>

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就是爱搞怪 2024-11-07 13:37:28

您关于错误使用开关条件的说法是正确的，“case”是开关中表达式的计算结果。

你应该使用 if 语句，但你可以使用这样的 switch 语句

switch (weapon === "paper") {
case true:
   //do something
   break;
case false:
   // do something else
default:
   // oh no! it wasn't true of false
}

You are correct about using the switch condition incorrectly, the "case" is what the expression in your switch evaluates to.

you should be using if statements, but you can use a switch statement like this

switch (weapon === "paper") {
case true:
   //do something
   break;
case false:
   // do something else
default:
   // oh no! it wasn't true of false
}

回复收藏 0 原文

安静被遗忘 2024-11-07 13:37:28

case 用于测试简单值，通常是数字。对于你的情况，我建议为石头、剪刀、布分配数字，这样这些数字的顺序就可以清楚地表明谁赢了。例如，石头=0，布=1，剪刀=2。然后，(3 + (a - b)) % 3 会告诉您谁赢了：0 表示平局，1 表示 a 获胜，2 表示 b 赢了。然后，您可以对该操作的结果执行简单的三例切换。