NumberConverter Java Program

// Sammy Samkough
// NumberConverter
// Spec: To convert numbers to different bases (Binary, Octal, Decimal, Hexadecimal).

public class NumberConverter
{
	private int decimal; 	// always stores the decimal equivalent, regardless of base
	private int base;
	private String strValue;
	private boolean b;

	/** default set to base 10 w/ a value of 0 */
	public NumberConverter()
	{
		decimal = 0;
		base = 10;
		strValue = "0";
	}

	/** base 10 value is used to set decimal, base and strValue
	* note: toBaseX can do this for you also */
	public NumberConverter(int value)
	{
		decimal = value;
		base = 10;
		strValue = toBaseX(10);
	}

	/** sets the strValue and base based on parameters
	*		 strValue is only stored in uppercase
	*		 decimal is set here as well provided newValue is valid */
	public NumberConverter(String newValue, int newBase)
	{
		strValue = newValue;
		base = newBase;
	}

	//**** Accessor Methods ****//
	public String getValue()
	{
		return strValue;
	}

	public int getBase()
	{
		return base;
	}

	public int getDecimal()
	{
		return decimal;
	}

	/** sets the strValue and base based on parameters
	*	 decimal is set here as well, with a call to baseXToDec() */
	public void setValue(String newValue, int newBase)
	{
		strValue = newValue;
		base = newBase;
		decimal = baseXToDec();
		b = this.isValid(); // validates the strValue by using the isValid() method
	}


	public boolean isValid()
	{
		boolean valid = true;

		//Checks for base 2
		if(base < 3)
		{
			for(int i = 0 ; i < strValue.length() - 1 ; i++)
			{
				if(charToValue(strValue.charAt(i)) < 0 || charToValue(strValue.charAt(i)) > 1)
				{
					valid = false;
					break;
				}
				else
				{
					valid = true;
				}
			}
		}
		//checks for bases 3 to 9
		else if(base < 10 && base > 2)
		{
			for(int i = 0 ; i < strValue.length() - 1 ; i++)
			{
				if(charToValue(strValue.charAt(i)) < 0 || charToValue(strValue.charAt(i)) >= 8)
				{
					valid = false;
					break;
				}
				else
				{
					valid = true;
				}
			}
		}
		//checks for 10 to 16
		else if(base >= 10 && base < 17)
		{
			for(int i = 0 ; i < strValue.length() - 1 ; i++)
			{
				if(charToValue(strValue.charAt(i)) < 0 || charToValue(strValue.charAt(i)) > 15)//this statement makes sure no value other than the known hex values occur
				{
					valid = false;
					break;
				}
				else
				{
					valid = true;
				}
			}
		}
		return valid;
	}

	/** base of this object is set to x and strValue is the String value in base x
	*   strValue is also returned, just for good measure
	*	@param x the number base to convert to */
	public String toBaseX(int x)
	{
		String strRev = "";
		strValue = "";
		int div = decimal;
		int mod = 0;
		base = x;

		if(b)
		{
			while(div != 0)
			{
				mod = div % base;
				if(mod >= 10) // the letter's number value
				{
					strValue += (char)(mod + 55);
				}
				else // numbers values for numbers 1 to 9
				{
					strValue += (char)(mod + 48);
				}
				div = (int)(div / base);
				strRev = reverseString(strValue); // reverses the strValue in order to return the accurate format
			}
		}
		else
		{
			strRev = "invalid";
		}

		return strRev;
	}

	/** take the currently stored strValue and calculate and return the decimal value */
	public int baseXToDec()
	{
		int exp = 0;
		decimal = 0;
		for(int i = strValue.length() - 1; i >= 0; i--) //goes from right to left on the strValue
		{
			decimal += charToValue(strValue.charAt(i)) * Math.pow(base, exp);
			exp++;
		}

		return decimal;
	}

	/** this is a helper method only
	*		 the integer value of digit is returned
	*		 -1 is the return value for an error
	* 	@param ch a valid digit for the given number base */
	private int charToValue(char ch)
	{
		int value = 0;
		switch(ch)
		{
			// gives values of 0-9 as 0-9 and A-F as 10-15
			case '0': value = 0;
			break;
			case '1': value = 1;
			break;
			case '2': value = 2;
			break;
			case '3': value = 3;
			break;
			case '4': value = 4;
			break;
			case '5': value = 5;
			break;
			case '6': value = 6;
			break;
			case '7': value = 7;
			break;
			case '8': value = 8;
			break;
			case '9': value = 9;
			break;
			case 'A': value = 10;
			break;
			case 'B': value = 11;
			break;
			case 'C': value = 12;
			break;
			case 'D': value = 13;
			break;
			case 'E': value = 14;
			break;
			case 'F': value = 15;
			break;
			// if none of the above occur, then the value is set to -1, which later in the isValid method will spell an error
			default: value = -1;
			break;
		}
		return value;
	}

	/** This is a helper method that returns strRev as a reversed version
	*	@param strFwd the string to be reversed  */
	public String reverseString(String strFwd)
	{
		String strReverse = "";

		for(int i = (strFwd.length() - 1); i >= 0; i--)
		{
			strReverse += strFwd.charAt(i);
		}

		return strReverse;
	}

	/** a String with the current base and value is returned */
	public String toString()
	{
		return "" + toBaseX(base);
	}
}
-----------------------------------------------------------------------------------------------------------------------------------
// Sammy Samkough
// NumberConverter
// Spec: To convert numbers to different bases (Binary, Octal, Decimal, Hexadecimal).

import java.util.Scanner;

public class NumberConverterClient
{
	public static void main(String args[])
	{
		boolean running = true;
		boolean playing = true;
		Scanner sc = new Scanner(System.in);
		NumberConverter nc = new NumberConverter();
		String v = "";
		String c = "";
		int b;

		while(running)
		{
			playing = true;

			System.out.print("What base do you want to start at? ");
			b = sc.nextInt();
			System.out.print("\nGood choice! Now enter the value you want converted: ");

			v = sc.next();
			v = v.toUpperCase();

			nc.setValue(v, b);
			System.out.println("\nYour number in binary is: " + nc.toBaseX(2));
			System.out.println("Your number in octal is: " + nc.toBaseX(8));
			System.out.println("Your number in decimal is: " + nc.toBaseX(10));
			System.out.println("Your number in base 12 is: " + nc.toBaseX(12));
			System.out.println("Your number in hexadecimal is: " + nc.toBaseX(16));
			System.out.println("----------------------------------------------------");
			System.out.println("Want to go again? Please choose either yes or no.");

			while(playing)
			{
				c = sc.next();
				if(c.equalsIgnoreCase("yes"))
				{
					System.out.println("----------------------------------------------------");
					playing = false;
					continue;
				}
				else if(c.equalsIgnoreCase("no"))
				{
					System.out.println("Bye-bye then!");
					playing = false;
					running = false;
					break;
				}
				else
				{
					System.out.println("Improper input. Try again");
					System.out.println("");
					continue;
				}
			} // smaller while loop, "playing"
		} // large while loop, "running"
	} // main method
} // class
/*
What base do you want to start at? 16

Good choice! Now enter the value you want converted: FFF

Your number in binary is: 111111111111
Your number in octal is: 7777
Your number in decimal is: 4095
Your number in base 12 is: 2453
Your number in hexadecimal is: FFF
----------------------------------------------------
Want to go again? Please choose either yes or no.
yes
----------------------------------------------------
What base do you want to start at? 16

Good choice! Now enter the value you want converted: BaD

Your number in binary is: 101110101101
Your number in octal is: 5655
Your number in decimal is: 2989
Your number in base 12 is: 1891
Your number in hexadecimal is: BAD
----------------------------------------------------
Want to go again? Please choose either yes or no.
yes
----------------------------------------------------
What base do you want to start at? 16

Good choice! Now enter the value you want converted: BAT

Your number in binary is: 101110011111
Your number in octal is: 5637
Your number in decimal is: 2975
Your number in base 12 is: 187B
Your number in hexadecimal is: B9F
----------------------------------------------------
Want to go again? Please choose either yes or no.
yes
----------------------------------------------------
What base do you want to start at? 10

Good choice! Now enter the value you want converted: 942

Your number in binary is: 1110101110
Your number in octal is: 1656
Your number in decimal is: 942
Your number in base 12 is: 666
Your number in hexadecimal is: 3AE
----------------------------------------------------
Want to go again? Please choose either yes or no.
yes
----------------------------------------------------
What base do you want to start at? 8

Good choice! Now enter the value you want converted: 747

Your number in binary is: 111100111
Your number in octal is: 747
Your number in decimal is: 487
Your number in base 12 is: 347
Your number in hexadecimal is: 1E7
----------------------------------------------------
Want to go again? Please choose either yes or no.
yes
----------------------------------------------------
What base do you want to start at? 12

Good choice! Now enter the value you want converted: A359b

Your number in binary is: 110100000110000111
Your number in octal is: 640607
Your number in decimal is: 213383
Your number in base 12 is: A359B
Your number in hexadecimal is: 34187
----------------------------------------------------
Want to go again? Please choose either yes or no.
yes
----------------------------------------------------
What base do you want to start at? 2

Good choice! Now enter the value you want converted: 1011101

Your number in binary is: 1011101
Your number in octal is: 135
Your number in decimal is: 93
Your number in base 12 is: 79
Your number in hexadecimal is: 5D
----------------------------------------------------
Want to go again? Please choose either yes or no.
yes
----------------------------------------------------
What base do you want to start at? 16

Good choice! Now enter the value you want converted: 16>;3

Your number in binary is: invalid
Your number in octal is: invalid
Your number in decimal is: invalid
Your number in base 12 is: invalid
Your number in hexadecimal is: invalid
----------------------------------------------------
Want to go again? Please choose either yes or no.
fad
Improper input. Try again

no
Bye-bye then!
Press any key to continue . . .
*/