Question

我必须使程序掷2个骰子100次，并计算总和等于7的时间。

我尝试做一个for count循环来计算总和= 7，但我认为我在逻辑上偏离了基础。

 //    int i = 0;       No. of rolls
 //    int count = 0;   No. of rolls = to 7

    for (int i = 0; i <= 100; i++){
        int dice1 = randomGenerator.nextInt(7);
        int dice2 = randomGenerator.nextInt(7);
        int sum = (dice1 + dice2);
        System.out.println(dice1 + ", " + dice2 + ", total: " + sum + " roll: " + i);
    }

    for (int count = 0; count++) {
        System.out.println(count);
    }

    System.out.println("Total number of time sum equaled 7 was " + count);

我正确地获得了随机掷骰，掷骰数和骰子总和，只需要弄清楚如何添加总和= 7个计数，我就会陷入困境。

Answer 1

这是使用流的另一个答案

 public static void main(String[] args){
      Random rng = new Random();
      long result = IntStream
          .generate(() -> rng.nextInt(6) + rng.nextInt(6) + 2)
          .limit(100)
          .filter(x -> x == 7)
          .count();
      System.out.println("Total number of time sum equaled 7 was " + result);
}

Answer 2

只需将您的for (int count = 0; count++) { ... }替换为if (sum==7) count++，然后放在int sum = (dice1 + dice2);之后

如果您的100个双骰子掷骰循环中的总和为7，则会增加计数。

要删除错误的骰子范围（0-7，请参阅评论@Robby Cornelissen），只需执行randomGenerator.nextInt(6)+1。

    int count = 0; //  No. of rolls = to 7

    for (int i = 0; i <= 100; i++){
        int dice1 = randomGenerator.nextInt(6)+1;
        int dice2 = randomGenerator.nextInt(6)+1;
        int sum = (dice1 + dice2);
        if (sum==7) count++;
        System.out.println(dice1 + ", " + dice2 + ", total: " + sum + " roll: " + i);
    }

    System.out.println("Total number of time sum equaled 7 was " + count);

Answer 3

使用Java 8，程序如下所示：

public class Dice
{
    static int count = 0;
    static Random ran = new Random();
    public static void main(String[] args)
    {
        IntStream.rangeClosed(1, 100). // iterates 1 to 100
            parallel().// converts to parallel stream
            forEach(i -> {
                rollDiceAndCheckIfSumIs7();
            });// prints to the console
        System.out.println("Out of 100 times, total number of times, sum was 7 is :" + count);

    }

    private static void rollDiceAndCheckIfSumIs7()
    {
        int dice1 = ran.nextInt(7);
        int dice2 = ran.nextInt(7);
        count += (dice1 + dice2 == 7) ? 1 : 0;
    }
}

如何计算时间总和= 7？

3 个答案: