IntegerToWord.java

/*	This program converts numbers into its word counterparts.
	This can only handle integer inputs from -999 to 999.
*/

import java.util.Scanner;

public class IntegerToWord
{
	public static void main(String[] args) 
	{
		Scanner s = new Scanner(System.in);
		System.out.print("Enter a # (bet. -999 to 999): ");
		int submit = s.nextInt();											// User Input

		int num = Math.abs(submit);											// Turns negative input to Positive Input

		int hundreds = num / 100;											// Gets the left most digit (hundreds) of the Input
		
		int ones = num % 10;												// Gets the right most digit (ones) of the Input

		int digitMiddleRight = num % 100;									// Gets the Middle digit (tens) and Right Digit (ones).
		
		int tens = digitMiddleRight / 10;									// It is now possible to get the middle digit (tens).


		if(num >= -999 && num <= 999){										// Input must be within this range.
			if (submit < 0)													// Checks if USER INPUT is negative.
			{
				System.out.print("Negative ");								// Prints NEGATIVE. The first word if the USER INPUT is Negative.
			}
			else if(num == 0)												// If Input is 0. then Zero
			{
				System.out.println("Zero");
			}
			else
			{
				System.out.print("");										// If Input is Positive. Just leave blank.
			}

			if(hundreds >= 1)												// Remember that int hundreds was used to get the left most digit.
			{
				switch(hundreds)
				{
					case 1: System.out.print("One hundred "); break;
					case 2: System.out.print("Two hundred "); break;
					case 3: System.out.print("Three hundred "); break;
					case 4: System.out.print("Four hundred "); break;
					case 5: System.out.print("Five hundred "); break;
					case 6: System.out.print("Six hundred "); break;
					case 7: System.out.print("Seven hundred "); break;
					case 8: System.out.print("Eight hundred "); break;
					case 9: System.out.print("Nine hundred "); 
				}
			}

			// This If-Else statement will only run if (USER_INPUT % 100) has a value.

			if(digitMiddleRight >= 11 && digitMiddleRight <= 19)			// If (USER INPUT % 100) has a value between the range 11 to 19.
			{
				switch(digitMiddleRight)
				{
					case 11: System.out.print("Eleven "); break;
					case 12: System.out.print("Twelve "); break;
					case 13: System.out.print("Thirteen "); break;
					case 14: System.out.print("Fourteen "); break;
					case 15: System.out.print("Fifteen "); break;
					case 16: System.out.print("Sixteen "); break;
					case 17: System.out.print("Seventeen "); break;
					case 18: System.out.print("Eighteen "); break;
					case 19: System.out.print("Nineteen "); 
				}	
			}
			else 															// if (USER INPUT % 100) is not equal to the values in the range 11-19
			{
				switch(tens)												// The middle digit.
				{
					case 1: System.out.print("Ten "); break;
					case 2: System.out.print("Twenty "); break;
					case 3: System.out.print("Thirty "); break;
					case 4: System.out.print("Forty "); break;
					case 5: System.out.print("Fifty "); break;
					case 6: System.out.print("Sixty "); break;
					case 7: System.out.print("Seventy "); break;
					case 8: System.out.print("Eighty "); break;
					case 9: System.out.print("Ninety "); 
				}

				switch(ones)												// Right most digit.
				{
					case 1: System.out.print("One "); break;
					case 2: System.out.print("Two "); break;
					case 3: System.out.print("Three "); break;
					case 4: System.out.print("Four "); break;
					case 5: System.out.print("Five "); break;
					case 6: System.out.print("Six "); break;
					case 7: System.out.print("Seven "); break;
					case 8: System.out.print("Eight "); break;
					case 9: System.out.print("Nine "); 						// Notice how System.out.print() is commonly used. Since this SOP statement prints on the same line and shit.
				}
			}
		}
		else
		{
			System.out.print("Invalid Value!");								// If the inputted value IS NOT in range -999 to 999.
		}
	s.close();
	}	
}