CODEWITHSUNDEEP
java
Intelligent
Intelligent

Reputation: 127

do while loop exit base on condition being specify

In my code, I want the loop to exit if the user enters an empty string for either variables. Nothing seems to work after I enter an empty string.

Where am I going wrong?

import java.util.HashMap;
import java.util.*;

public class Main {

    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        String lakeName;
        String timeRun;

        HashMap<String, Double> newMap = new HashMap<>();

        do {
            System.out.println("Enter the Lake Name");
            lakeName = input.nextLine();
            System.out.println("Enter number of minutes run");
            timeRun = input.nextLine();
            Double finalRun = Double.parseDouble(timeRun);
            newMap.put(lakeName, finalRun);

            if(lakeName.equalsIgnoreCase("") || timeRun.equalsIgnoreCase("")){

                break;
            }

        } while(true);

        for(String key: newMap.keySet()){
            Double value = newMap.get(key);
            System.out.println(key + ": "+ value);
        }        
    }
}

Upvotes: 1

Views: 45

Answers (3)

Stefan Dollase
Stefan Dollase

Reputation: 4620

When you enter an empty string for the timeRun, you will try to parse an empty string as double. This fails and throws this exception:

java.lang.NumberFormatException: empty String

You can solve this by placing the following code into the loop:

        System.out.println("Enter the Lake Name");
        lakeName = input.nextLine();
        System.out.println("Enter number of minutes run");
        timeRun = input.nextLine();
        if (lakeName.equalsIgnoreCase("") || timeRun.equalsIgnoreCase("")) {
            break;
        }
        Double finalRun = Double.parseDouble(timeRun);
        newMap.put(lakeName, finalRun);

I just moved the break up a few lines, including its condition.

Also, you can replace the .equalsIgnoreCase("") by .isEmpty(), as already stated in the other answer.

Upvotes: 2

qiang.wei.kang
qiang.wei.kang

Reputation: 176

try this :

 do {
    System.out.println("Enter the Lake Name");
    lakeName = input.nextLine();
    System.out.println("Enter number of minutes run");
    timeRun = input.nextLine();
    if(lakeName.equalsIgnoreCase("") || timeRun.equalsIgnoreCase("")){

        break;
    }
    Double finalRun = Double.parseDouble(timeRun);
    newMap.put(lakeName, finalRun);



} while(true);

put the if{...} up, if not , it will be given NumberFormatException.

Upvotes: 3

Faraz
Faraz

Reputation: 6265

One way to do is to check if String is isEmpty(), put a break statement.

So in your case it would be like:

if(lakeName.isEmpty())
   break;

You gotto do the same thing with timeRun variable;

Upvotes: 2

Related Questions