Asking the user for input until they give a valid response java

Question

Problem:

So, guys, I am learning to handle the java scanner class and taking input from the user. Let’s come to my point quickly. I was thinking to write a java program that asking the user for input until they give a valid response. I do have an idea to make it inside my head.

1. Taking input by using scanner class
2. Pass it through a true-false condition
3. Print something according to the true-false condition

So, this is my raw flow-chart to write the program. Please correct me if I am wrong anywhere. Any sample program is appreciated.

Answer 1

Well, your flow-chart looks good. It’s always better to give it a try to write code. Let’s write a code using the scanner class by following your given flowchart.

import java.util.Scanner;

public class Prompting{

     public static void main(String []args){
         Scanner in = new Scanner (System.in);
         boolean valid = false;
         double input = 0;
         while(!valid){
             System.out.println("Enter a positive value<100 : ");
             input = in.nextDouble();
             if (input>0 && input<100){
                 valid = true;
                 System.out.println("This is a good number");
             }
             else{
                 System.out.println("Sorry! Invalid Input");
             }
         }
     }
}

As per your flowchart, I made this program. Here, this program will take input and check it if it matches our requirement. It counts only 0 to 100 positive numbers except all it throws back Sorry Invalid Input.

So, run the program and let me know if you have got any questions in the future regarding this issue. Please reply to this thread.
Thanks.