Question

对不起基本问题 - 刚开始使用JAVA

尝试验证值用户在按顺序输入下一个值之前输入 - 程序按顺序运行到下一个if语句，而不是让我重新输入开始时间......

System.out.println("Enter start time in 24 hr format eg 0800 "); 
startTime = in.nextInt();

  if (startTime >=0000 && startTime <=2400) // verify hours
        {
        System.out.println ( "thank you start hours entered  ");
        }
  else
        if (startTime >2400 )  // verify hours
        {
        System.out.println ( "invalid start hours ! please re-enter ");
        }


System.out.println("Enter stop time in 24 hr format eg 1700 "); 

  stopTime = in.nextInt();

        if (stopTime >=0000 && stopTime <=2400) // verify hours
        {
        System.out.println ( "thank you stop hours entered  ");
        }
        else
          if (stopTime >2400 )
          {
          System.out.println ( "invalid stop hours ! please re-enter ");
          }

   // proceed with rest of program

Answer 1

您应该查看while循环。 E.g。

do{
 stopTime = in.nextInt();
} while (!(stopTime >=0000 && stopTime <=2400));

Answer 2

以下是您打算做的完整代码：

import java.util.Scanner;

public class VerifyUserInput {

    public static void main(String[] args) {
        int hours = 0;
        int minutes = 0;
        Scanner sc = new Scanner(System.in);
        boolean verifyStartTime=true;

        // Get the input for start time and then Verify
        do {
            System.out.println("Enter Start Time :");
            System.out.println("Enter the Hour component from 00-24 :");
            hours =sc.nextInt();
            System.out.println("Enter the Minutes component from 00-60 :");
            minutes = sc.nextInt();
            String startTime = "";
            if(hours > -1 && hours <=24) {
                if(minutes >-1 && hours <=60) {
                    startTime = hours+":"+minutes;
                    System.out.println("The Time entered is valid :"+startTime);
                }
                verifyStartTime = false;
            }else {
                System.out.println("Please Try Again !");
            }
        }while(verifyStartTime);

        boolean verifyEndTime=true;
        // Get the input for End time and then Verify
        do {
            System.out.println("Enter End Time :");
            System.out.println("Enter the Hour component from 00-24 :");
            hours =sc.nextInt();
            System.out.println("Enter the Minutes component from 00-60 :");
            minutes = sc.nextInt();
            String endTime = "";
            if(hours > -1 && hours <=24) {
                if(minutes >-1 && hours <=60) {
                    endTime = hours+":"+minutes;
                    System.out.println("The Time entered is valid :"+endTime);
                }
                verifyEndTime = false;
            }else {
                System.out.println("Please Try Again !");
            }
        }while(verifyEndTime);
    }
}

另请考虑@sanchises

的评论

如果值不正确，请让用户重新输入值

2 个答案: