java扫描程序输入验证导致循环提前结束

mm9b1k5b  于 2021-07-14  发布在  Java
关注(0)|答案(2)|浏览(281)

我用for循环填充一个双数组,循环运行用户在第4行输入的圈数。然而,正如我在图片中展示的:
我输入3圈,问题提示3次,但是我的数据验证会吃掉我正在寻找的输入之一。
我该怎么解决这个问题?我觉得这很简单。

import java.util.Scanner;
public class JK_FINALPRAC1 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("Time-Trial Statistics Program\n");
        System.out.println("This program will ask you to input split-times for each lap or length of a race. The ");
        System.out.println("program will then calculate some basic statistics from the split-times.\n");

        System.out.print("Enter the number of laps or lengths in the race: ");
        int arraySize = sc.nextInt();
        Double[] lapArray = new Double[arraySize];
        System.out.println("Now input the elapsed time (split time) in seconds for each lap/length of the race.");
        int index = 1;
        double currentNum = 0.0;
        for(int i=0;i<arraySize;i++){
            System.out.print("Time for lap or length #" + index + ": ");
            currentNum = sc.nextDouble();
            if(currentNum > 0 && currentNum < 61){
            lapArray[i] = currentNum;
            index++;
            }else if(currentNum<0 || currentNum >60){
            System.out.println("Invalid input! Time must be between 0 and 60.");
            }
        }

    }

5kgi1eie

5kgi1eie1#

double currentNum = 0.0;
        while (index < arraySize) {
            System.out.print("Time for lap or length #" + (index + 1) + ": ");
            currentNum = sc.nextDouble();
            if (currentNum > 0 && currentNum < 61) {
                lapArray[index] = currentNum;
                index++;
            } else if (currentNum < 0 || currentNum > 60) {
                System.out.println("Invalid input! Time must be between 0 and 60.");
            }
        }

因为您正在运行for循环,所以每次i都会递增(即使验证失败)。

uelo1irk

uelo1irk2#

它非常简单:为了确保你插入了一个双人而不吃一圈,把你的扫描仪输入线放在一个while循环中

do{
    double x = scanner.nextDouble(); 
 }while(x < 0 || x > 60);

除非do while的条件为false,否则这将无法承受循环递增计数器。
为了打印验证:

double x = scanner.nextLine();
 while( x < 0 || x > 60){
      //print message
      //scanner again
 }

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