Convert Kilometers to Miles, Meters, and Centimeters in Java

Topic

In this Java program, you will learn how to convert a distance given in kilometers to three different units: miles, meters, and centimeters. This is a basic conversion program that helps beginners practice variables, arithmetic operations, and printing formatted output in Java.

The key concepts involved include:

• Understanding of data types like double
• Arithmetic operations and conversion factors
• Printing results with System.out.println

Examples

Example 1:
Input: 1.0 km
Output:
Miles: 0.621371
Meters: 1000.0
Centimeters: 100000.0

Example 2:
Input: 0.0 km
Output:
Miles: 0.0
Meters: 0.0
Centimeters: 0.0

Example 3:
Input: 3.5 km
Output:
Miles: 2.1747985
Meters: 3500.0
Centimeters: 350000.0

Interviewer Expectations

The interviewer expects you to:

• Know how to take input (if required) and perform unit conversions using constants.
• Demonstrate proper use of data types, especially double for precision.
• Format your program clearly with logical variable naming and output structure.

Approach

To convert kilometers into different units:

• 1 kilometer = 1000 meters
• 1 kilometer = 100000 centimeters
• 1 kilometer = 0.621371 miles

Steps:

1. Declare a variable to store distance in kilometers.
2. Multiply it by the respective conversion factors to get other units.
3. Print each result using System.out.println().

Dry Run:

Input: 2.0 km

Calculations:

• Miles = 2.0 * 0.621371 = 1.242742
• Meters = 2.0 * 1000 = 2000
• Centimeters = 2.0 * 100000 = 200000

Output: Miles: 1.242742, Meters: 2000.0, Centimeters: 200000.0

Java Program

public class DistanceConverter {
  public static void main(String[] args) {
    double kilometers = 5.0;
    double miles = kilometers * 0.621371;
    double meters = kilometers * 1000;
    double centimeters = kilometers * 100000;

    System.out.println("Miles: " + miles);
    System.out.println("Meters: " + meters);
    System.out.println("Centimeters: " + centimeters);
  }
}

Miles: 3.106855
Meters: 5000.0
Centimeters: 500000.0

Convert Kilometers

Possible Followup Questions with Answers

Q1: How would you convert kilometers to feet and inches?

1 kilometer = 3280.84 feet, and 1 kilometer = 39370.1 inches. Use similar multiplication as we did earlier.

double feet = kilometers * 3280.84;
double inches = kilometers * 39370.1;

Q2: What if the input comes from the user?

You can use Scanner to take input from the user:

Scanner sc = new Scanner(System.in);
System.out.print("Enter kilometers: ");
double km = sc.nextDouble();

Q3: Why do we use double instead of int for these conversions?

Because many converted values (like miles or inches) are not whole numbers. Using double ensures accurate decimal values.