Question

输入“ q”后程序不会停止；它仍然会打印随机数及其总和。我希望程序在输入“ q”后立即完全停止。

import java.util.Scanner;
import java.util.Random;
public class lab7
{
public static void main(String[] args)
{
    Scanner input = new Scanner(System.in);
    Random rand = new Random();
    String letter = " ";
    int num = 0;
    System.out.print("Push your luck");
      */the program prints push your luck! 
    while(!letter.equals("q")){
        int sum = rand.nextInt(12);
        System.out.println(" ");
        letter = input.nextLine();
         */ the program should not print random number or sum when input "q" 
         */but in this case it does
        System.out.println("Random number: " + sum);
        System.out.println("Updated number: " + num);
        num = num + sum;
}
}
}

Answer 1

首先给变量赋予有意义的名称。因此，sed -e "s/\(,'[^']*\)'\([^']*@[^']*',\)/\1\2/"应该是num，而sum应该是sum。
接下来，像这样在循环内重新排列代码：

num

循环中的Scanner input = new Scanner(System.in); Random rand = new Random(); String letter = " "; int sum = 0; System.out.print("Push your luck"); while (!letter.equals("q")) { int num = rand.nextInt(12); System.out.println(" "); letter = input.nextLine(); if (!letter.equals("q")) { sum = sum + num; System.out.println("Random number: " + num); System.out.println("Updated number: " + sum); } }语句可防止在输入if时执行任何其他代码。

Answer 2

看起来像你想做的：

letter = input.nextLine();
while(!letter.equals("q")) {
    int sum = rand.nextInt(12);
    System.out.println(" ");
    System.out.println("Random number: " + sum);
    System.out.println("Updated number: " + num);
    num = num + sum;
    letter = input.nextLine();
}

Answer 3

只需将输入移动到循环的最后一行，并在前面添加一个输入即可。这样一来，总是在收到输入后立即检查循环条件。

letter = input.nextLine();
while(!letter.equals("q")){
        int sum = rand.nextInt(12);
        System.out.println(" ");
        System.out.println("Random number: " + sum);
        System.out.println("Updated number: " + num);
        num = num + sum;
        letter = input.nextLine();
}

Answer 4

您可以创建一个if子句来检查是否输入了q，并使用break;语句停止它。在这种情况下，continue语句也适用。

Answer 5

一个for循环应该做。

for(String aletter = input.nextLine();!aletter.equals("q");aletter=input.nextLine()) { 
    int sum = rand.nextInt(12);
    System.out.println(" ");
    System.out.println("Random number: " + sum);
    System.out.println("Updated number: " + num);
    num = num + sum;
}

而且，由于您不使用输入，因此可以将其简化：

while(!input.nextLine().equals("q")) { 
    int sum = rand.nextInt(12);
    System.out.println(" ");
    System.out.println("Random number: " + sum);
    System.out.println("Updated number: " + num);
    num = num + sum;
}

如果您想要至少一个输出，然后才能使用“ q”将其停止：

do { 
    int sum = rand.nextInt(12);
    System.out.println(" ");
    System.out.println("Random number: " + sum);
    System.out.println("Updated number: " + num);
    num = num + sum;
}while(!input.nextLine().equals("q"));

输入“ q”后如何完全结束循环？

5 个答案: