Question

Write a Java program which displays wore equivalent of a number of only 3 digits, that is 123 should be displayed as one hundred twenty three.

Short answer

The Java program should use methods to convert number parts into words and combine them to display full words for numbers.

Step-by-step solution

Import Necessary Packages

Start by importing necessary classes in your Java program. For this problem, you might use the 'java.util.Scanner' package to take input if needed.

Create a Class and Main Method

Define your public class, say 'NumberToWords', and create the main method within it. This is where your program will start executing.

Write a Method to Convert Hundreds Digit

Implement a method, such as 'convertHundreds', that will take an integer from 1 to 9 and return the word representation ('one hundred', 'two hundred', etc.). Use an array or switch-case to map numbers to words.

Write a Method for Tens and Units below Twenty

Create a method called 'convertBelowTwenty', which will handle numbers from 0 to 19. Use an array to map direct conversions since these numbers have special words like 'eleven', 'twelve', etc.

Write a Method for Tens Digit

Design a method named 'convertTens' for handling the tens place for numbers 20 and above (20, 30, ... 90). Use an array for easy mapping of tens to words ('twenty', 'thirty', etc.).

Combine Methods to Handle All Cases

In the main method or another method, combine all previous methods to handle numbers from 100-999. Break down the number into hundreds, tens, and units, and use the respective methods to convert each part to words.

Print the Final Result

Once the whole number has been converted in words, print the final result. For instance, "123" should be a call to print the words 'one hundred twenty three'.

Key concepts

Java programming

Java is a high-level programming language known for its platform independence, robustness, and simplicity. These features make it a popular choice for developers working on various applications, from mobile apps to enterprise-level solutions. Java's syntax is inspired by C++, but it offers easier memory management and built-in libraries, enhancing productivity among developers.
Java is both object-oriented and class-centric, allowing for the development of modular, reusable code. Applications are usually written once and can run anywhere, meaning they don't need to be recompiled to execute on different devices or platforms.

• Platform Independence: Java programs can execute on any device that has the Java Virtual Machine (JVM).
• Object-Oriented: Java supports the creation of objects which encapsulate data and behavior.
• Secure and Robust: Automatic garbage collection and error checking at both compile and runtime make Java reliable and secure.

convert numbers to words

Converting numbers to words in Java involves breaking down numbers into their constituent parts and then mapping these parts to corresponding English words. This requires careful handling of different components of a number.
For example, the number 123 can be broken down into hundreds, tens, and units. In this case, you split 123 into 100 (one hundred), 20 (twenty), and 3 (three). By handling each part separately, we ensure clarity and accuracy in conversion.

• Hundreds: The number in the hundreds position is converted directly to words, such as 'one hundred', 'two hundred'.
• Tens: For numbers 20 and above, each ten is mapped to words like 'twenty', 'thirty'.
• Units and Teens: Numbers from 0 to 19 have unique words, including compound words like 'eleven', or direct numbers like 'fourteen'.

Java can perform this conversion using if-statements, switch-case constructs, or through arrays for streamlined code.

Java methods

Methods in Java are blocks of code designed to perform specific tasks, eliminating redundancy. Not only do they enhance code readability by breaking down tasks into smaller pieces, but they also allow for code reuse.
Each method consists of a declaration and a body. The declaration includes access modifiers, return types, and method names. Inside the body, code defines what tasks the method will perform.

• Method Declaration: Specifies the method name, return type, parameters, and access level (public, private, etc.).
• Method Body: Contains the code that executes when the method is called. It can operate on input parameters and return a value or execute a specific action.
• DRY Principle: Java methods help keep code DRY (Don't Repeat Yourself) by enabling reuse of code blocks in different parts of a program.

Methods such as 'convertHundreds' and 'convertTens' help to articulate the number conversion logic into clear, manageable tasks, making them an invaluable part of your Java program design.

arrays in Java

Arrays in Java are data structures that store multiple values of the same type in a contiguous memory location. They are essential tools for organizing data efficiently, whether for accessing individual items or implementing complex algorithms.
Java arrays are declared with a fixed size, and each element within an array can be accessed using an index.

• Declaration and Initialization: Arrays are declared with a specific type and size, using syntax like `int[] numbers = new int[10];`.
• Accessing Elements: Through an index, you can access or modify elements. For example, `numbers[0]` will retrieve the first element.
• Array Features: Arrays can store primitive types as well as objects, making them versatile for tasks like numerical calculations or managing groups of related information.

When converting numbers to words, arrays can efficiently map numbers to their word equivalents, reducing code complexity. For example, an array might map index 10 to the word 'ten', simplifying the process of transforming numbers into phrases.