Question

我想知道如何在循环中获取变量并将其带到外面。这可能吗？

这是问题所在：

编写一个实现双人游戏的程序。计算机是得分守护者，两名运动员是人类。每轮游戏都从计算机开始随机选择从1.0到略低于100.0的双精度数。每个玩家估计数字的平方根并输入估计值。估计最接近正确的玩家赢得该回合。在每轮比赛中排名靠前的球员。播放在指定次数后结束。

多少回合？ 4 第一位玩家，登录 - ＆gt; Dweezle Secnd Player，登录 - ＆gt;月亮单位

83.29097831183603的平方根是多少？ Dweezle，你的猜测：9.1 Moon Unit，你的猜测：9.2 正确的平方根：9.126389116832353 Dweezle距离是0.026389116832353565 月亮单位是0.07361088316764608 Dweezle赢了！

87.79346957866132的平方根是多少？ Moon Unit，你的猜测：8.8 Dweezle，你的猜测：8.9 正确的平方根：9.36981694477866 Dweezle距离是0.46981694477866043 月亮单位是0.5698169447786601 Dweezle赢了！

67.44682032701256的平方根是多少？ Dweezle，你的猜测：8.2 Moon Unit，你的猜测：8.1 正确的平方根：8.212601313044033 Dweezle距离0.012601313044033446 月亮单位是0.11260131304403309 Dweezle赢了！

71.64725527288849的平方根是多少？ Moon Unit，你的猜测：8.4 Dweezle，你的猜测：8.45 正确的平方根：8.464470170831042 Dweezle距离0.01447017083104285 月亮单位是0.06447017083104178 Dweezle赢了！

----最终得分---- Dweezle：4月亮单位：0

这是我到目前为止所得到的。但是，由于某种原因，它会跳过String firstPlayer = scan.nextLine（）;部分代码并跳转到下一个代码。让我再次重复我的问题，你如何在循环中取一个变量并将其从中取出？非常感谢你们。

public static void main(String[] args) {
    System.out.println("This is the square root game. Only two players allowed.");

    Scanner scan = new Scanner(System.in);
    System.out.println("How many rounds are you two playing?");
    int numofRounds = scan.nextInt();

    System.out.println("First player, what is your name?");
    String firstPlayer = scan.nextLine();
    System.out.println();

    System.out.println("Second player, what is your name?");
    String secondPlayer = scan.nextLine();
    System.out.println();

    while (numofRounds > 0){
        Random rn = new Random();
        int range = 100;
        double randomNum =  rn.nextInt(range) + 1;
        System.out.println("What is the square root of " + randomNum + " ?");

        System.out.println(firstPlayer + ", your guess:");
        double firstPlayerInput = scan.nextDouble();

        System.out.println(secondPlayer + ", your guess:");
        double secondPlayerInput = scan.nextDouble();

        double sqrtRandom = java.lang.Math.sqrt(randomNum);
        System.out.println("The correct square root is: " + sqrtRandom);

        double firstDifference = java.lang.Math.abs(sqrtRandom - firstPlayerInput);
        System.out.println(firstPlayer + " is " + firstDifference + " away.");

        double secondDifference = java.lang.Math.abs(sqrtRandom - secondPlayerInput);
        System.out.println(secondPlayer + " is " + secondDifference + " away.");

        if (firstDifference < secondDifference) {
            int scoreFirst = 0;
            scoreFirst = scoreFirst + 1;                 
            System.out.println(firstPlayer + " wins! His/her score: " + scoreFirst);

        }
        if (secondDifference < firstDifference) {
            int scoreSecond = 0;
            scoreSecond = scoreSecond + 1;                
            System.out.println(secondPlayer + " wins! His/her score: " + scoreSecond);

        }
        else 
            System.out.println("This game is a tie.");

        numofRounds = numofRounds - 1;
    }
    System.out.println("---- Final Score ----");
    System.out.println(firstPlayer + ": " + scoreFirst + "" + secondPlayer + ": " + scoreSecond );

}

}

EDIT -------------------------------------------- 非常感谢所有的答案，他真的很乐意帮助!!!!!

Answer 1

您需要在循环之前声明变量。这样它的scope不限于循环内。像这样：

int scoreFirst = 0;
int scoreSecond = 0;
while (numOfRounds > 0) {
    // ...
}

Answer 2

简单的答案是在循环之前声明它们。

int n = 0;
while( true ){
    n = 1;
}
// n will retain it's value here

Answer 3

如果在循环外部声明变量，则可以在循环外部访问它，例如：

double d = 0;
while(soneCondition) {
    ...
    d = 1;
    ...
}
// the change to the variable is seen here

变量的可访问性由其定义的位置决定。

将变量置于循环内并将其从中取出？

3 个答案: