Convert One Unit to Another

In this section, you will learn to convert Grams to Pounds, Grams to Ounce, Kilograms to Pounds and Pounds to Kilograms. The following program helps you in converting one unit to another.

Code Description:

In this example we have taken a table of units as Grams, Kilograms, Pounds etc to convert them to another units. First of all it will ask to enter a choice then it will convert the unit. For the conversion process we have used GramsToPounds();, GramsToOunce();, KilogramsToPounds(); and PoundsToKilograms();. method. For the choice of entries we have used switch case here. At last we have applied the formulae for all the conversions as shown in the program.

We have also used conditional-OR operator to select the choice as 1,2 and so on. This means that the choice should be between 1 to 5 only. To take the input of the choice for TableChoice from the keyboard we have used the same method i.e Integer.parseInt(bf.readLine());.


import java.io.*;

import java.util.*;



public class UnitConverter{

 BufferedReader bf;

 public static void main (String[] args) throws Exception{

  UnitConverter Un = new UnitConverter();

    }

 public UnitConverter() throws Exception{

  bf = new BufferedReader(new InputStreamReader(System.in));

  int TableChoice;

  boolean done = false;

  while (!done) {

   TableChoice = runMenu();

   switch (TableChoice) {

    case 1: System.out.println("convertGramsToPounds");

    convertGramsToPounds();

    break;

    case 2: System.out.println("convertGramsToOunce");

    convertGramsToOunce();

    break;

    case 3: System.out.println("convertKilogramsToPounds"); 

    convertKilogramsToPounds();

    break;

    case 4: System.out.println("convertPoundsToKilograms"); 

    convertPoundsToKilograms();

    break;

    default: System.out.println(""Quiting..."");


System.exit(0); 

    break;

   }

  }

 }

 

 public int runMenu() throws Exception{

  int TableChoice;

  System.out.println();

  System.out.println("Conversion Table:");

  System.out.println("-------------------------");

  System.out.println("1. Grams To Pounds");

  System.out.println("2. Grams To Ounce");

  System.out.println("3. Kilograms To Pounds");

  System.out.println("4. Pounds To Kilograms");

  System.out.println("5. Quit");

  System.out.println("-------------------------");

  System.out.print("Choice: ");

  TableChoice = Integer.parseInt(bf.readLine());

  while (TableChoice < 1 || TableChoice > 5) {

   System.out.print("Invalid choice, try again: ");

   TableChoice = Integer.parseInt(bf.readLine());

  }

  System.out.println();

  return TableChoice;

 }

 

 public void convertGramsToPounds() throws Exception{

  System.out.print("Enter the Grams:");

  int gram = Integer.parseInt(bf.readLine());

  double pound = gram * 0.00220462262;

  System.out.println("Pound: " + pound);

 }

 

 public void convertGramsToOunce() throws Exception{

  System.out.print("Enter the Grams:");

  int gram = Integer.parseInt(bf.readLine());

  double Ounce = gram * 0.035273962;

  System.out.println("Ounce:" + Ounce);

 }

 

 public void convertKilogramsToPounds() throws Exception{

  System.out.print("Enter the Kilogram:");

  int kilo = Integer.parseInt(bf.readLine());

  double pond = kilo * 2.20462262;

  System.out.println("Ponds: " + pond);

 }

 

 public void convertPoundsToKilograms() throws Exception{

  System.out.println("Enter the Pounds:");

  int pound = Integer.parseInt(bf.readLine());

  double kilo = pound * 0.45;

  System.out.println("Kilo: " + kilo);

 }

}

Output of the program:

C:\unique>javac UnitConverter.java

C:\unique>java UnitConverter

Conversion Table:
-------------------------
1. Grams To Pounds
2. Grams To Ounce
3. Kilograms To Pounds
4. Pounds To Kilograms
5. Quit
-------------------------
Choice: 1

convertGramsToPounds
Enter the Grams:1
Pound: 0.00220462262

Conversion Table:
-------------------------
1. Grams To Pounds
2. Grams To Ounce
3. Kilograms To Pounds
4. Pounds To Kilograms
5. Quit
-------------------------
Choice: 4

convertPoundsToKilograms
Enter the Pounds:
1
Kilo: 0.45

Conversion Table:
-------------------------
1. Grams To Pounds
2. Grams To Ounce
3. Kilograms To Pounds
4. Pounds To Kilograms
5. Quit
-------------------------
Choice: 3

convertKilogramsToPounds
Enter the Kilogram:1
Ponds: 2.20462262

Conversion Table:
-------------------------
1. Grams To Pounds
2. Grams To Ounce
3. Kilograms To Pounds
4. Pounds To Kilograms
5. Quit
-------------------------
Choice: