Overview

In this tutorial, we will learn to develop a java program to convert distance in kilometers to miles. We will make use of the below formulas for the conversion. The mathematical formula for converting distance from kilometers to miles:

Miles = 0.62 * ( Distance in kilometers)

The mathematical formula for converting distance from miles to kilometers:

Kilometers = 1.60 * (Distance in miles )

Tools used

Tools used to develop the program are as follows:

• JDK
• IntelliJ IDE

Convert Distance Java Program

The program allows users to input the two conversion options. The program checks for the options 1 and 2. It stops gracefully for any other input options.

import java.util.Scanner;

public class DistanceConverter {
    public static void main(String args[]) {
        Scanner input = null;
        double km,mi,distance;
        int option;
        try {
            input = new Scanner(System.in);
            System.out.println("Choose an Option:");
            System.out.println("Convert Kilometers to Miles(1)");
            System.out.println("Convert Miles to Kilometers(2)");
            option = Integer.parseInt(input.nextLine());
            if (option != 1 && option != 2)
            {
                System.out.println("Plz choose option 1 or 2");
                System.exit(0);
            }
            if(option == 1) {
                System.out.println("Enter Distance in Kilometers");
                distance = Double.parseDouble(input.nextLine());
                mi = 0.62 * distance;
                System.out.println("Distance in Miles is:" + mi );

            }
            else if(option == 2) {
                System.out.println("Enter Distance in Miles");
                distance = Double.parseDouble(input.nextLine());
                km = 1.60 * distance;
                System.out.println("Distance in Kilometers is:" + km );
            }
        }
        catch(Exception e)
        {
            System.out.print("Error.Program Terminated");
        }
        finally
        {
            if (input != null) {
                input.close();
            }
        }
    }
}

 

Output of the program

Test Cases

Execute some test cases to verify the program output. We will execute two test cases on the program.

Test Case 1-> To verify the conversion from Kilometers to Miles option.

Test Case 2-> To verify the conversion from Miles to Kilometers option.

Test Case 3 -> This is an invalid test case. To verify how the program responds for invalid user input.

Test Case #1

Choose an Option:
Convert Kilometers to Miles(1)
Convert Miles to Kilometers(2)
1
Enter Distance in Kilometers
10
Distance in Miles is:6.2

Test Case #2

Choose an Option:
Convert Kilometers to Miles(1)
Convert Miles to Kilometers(2)
2
Enter Distance in Miles
10
Distance in Kilometers is:16.0

Test Case #3

Choose an Option:
Convert Kilometers to Miles(1)
Convert Miles to Kilometers(2)
3
Plz choose option 1 or 2

 

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