Conversions Works

Finished some unfinished conversions in Octal system.
Added Decimal to HexaDecimal conversion.

Conversions/DecimalToHexaDecimal.java

@@ -0,0 +1,33 @@
+import java.lang.StringBuilder;
+import java.util.Scanner;
+
+class Test {
+  private static final int sizeOfIntInHalfBytes = 8;
+  private static final int numberOfBitsInAHalfByte = 4;
+  private static final int halfByte = 0x0F;
+  private static final char[] hexDigits = { 
+    '0', '1', '2', '3', '4', '5', '6', '7', 
+    '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
+  };
+
+  public static String decToHex(int dec) {
+    StringBuilder hexBuilder = new StringBuilder(sizeOfIntInHalfBytes);
+    hexBuilder.setLength(sizeOfIntInHalfBytes);
+    for (int i = sizeOfIntInHalfBytes - 1; i >= 0; --i)
+    {
+      int j = dec & halfByte;
+      hexBuilder.setCharAt(i, hexDigits[j]);
+      dec >>= numberOfBitsInAHalfByte;
+    }
+    return hexBuilder.toString(); 
+  }
+
+  public static void main(String[] args) {
+    Scanner sc = new Scanner(System.in);
+      System.out.println("Write your Number to convert into HexaDecimal: ")
+     int dec = 305445566;
+     String hex = Integer.toHexString(dec);
+     String hex = decToHex(dec);
+     System.out.println(hex);       
+  }
+}

Conversions/OctalToBinary.java

@@ -28,7 +28,22 @@ public class OctalToBinary {
 	 * @return The binary number
 	 */
 	public static int convertOctalToBinary(int o) {
-		
-	}
+		Scanner scan;
+		int num;
 	
-}
+		void getVal() {
+		
+			System.out.println("Octal to Binary");
+			scan = new Scanner(System.in);
+			// Entering the needed number
+			System.out.println("\nEnter the number : ");
+			num = Integer.parseInt(scan.nextLine(), 8);
+		}
+		
+		void convert() {
+		
+			String binary = Integer.toBinaryString(num);		
+			System.out.println("Binary Value is : " + binary);
+		}
+	}
+}

Conversions/OctalToDecimal.java

@@ -28,7 +28,21 @@ public class OctalToDecimal {
 	 * @return The decimal number
 	 */
 	public static int convertOctalToDecimal(int o) {
-		
+		System.out.print("Octal Input: ");
+		// Read the input from the console which we are expecting as an octal number:
+		Scanner s = new Scanner(System.in);
+		String inputHex = s.nextLine();
+		try{
+			// Actual conversion of Octal to Decimal:
+			Integer outputDecimal = Integer.parseInt(inputHex, 8);
+			System.out.println("Decimal Equivalent : " + outputDecimal);
+		}
+		catch(NumberFormatException ne){
+			// Printing a warning message if the input is not a valid octal number:
+			System.out.println("Invalid Input, Expecting octal number 0-7");
+		}
+		finally{
+			s.close();
+		}
 	}
-
-}
+}