Finsihed

src/AssessmentPartThree.java

 
 public class AssessmentPartThree {
 
-	// The simplest form of encryption is the rotation cipher (also known as Caeser's Cipher)
-	// An offset value is chosen to encrypt a message. Each letter is replaced by the
-	// letter that that number of places away from it.
-	// So if an offset value of 1 is chosen, each letter is replaced by the one after it
-	// - so a becomes b, b becomes c, etc
-	// If a value of -2 is chosen a becomes y, b becomes z and so on
+	/* The simplest form of encryption is the rotation cipher (also known as Caeser's Cipher)
+	An offset value is chosen to encrypt a message. Each letter is replaced by the
+	letter that that number of places away from it.
+	So if an offset value of 1 is chosen, each letter is replaced by the one after it
+	- so a becomes b, b becomes c, etc
+	If a value of -2 is chosen a becomes y, b becomes z and so on
+	 */
 	
 	 public char enryptedCharacter(char theChar, int theOffset)
 	 {
-		 // 05 - encryptedCharacter
-		 // Complete this method so that it returns the encrypted character for
-		 // theChar when and offset of theOffset is used
-		 // So if theChar='m' and theOffset is 3 the method will return 'p'
-		 // Lower case characters remain lower case, upper case remain upper case
-		 // Any other characters are returned unchanged
+		 /* 05 - encryptedCharacter
+		 Complete this method so that it returns the encrypted character for
+		 theChar when and offset of theOffset is used
+		 So if theChar='m' and theOffset is 3 the method will return 'p'
+		 Lower case characters remain lower case, upper case remain upper case
+		 Any other characters are returned unchanged
+		  */
 		 char encChar = theChar;
+		 // Declaring upper and lower-case letters in a String
 		 String lowerCase = "abcdefghijklmnopqrstuvwxyz";
 		 String upperCase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 		 if(Character.isLetter(theChar))
@@ -24,15 +27,19 @@ public class AssessmentPartThree {
 			 // Seeing if the character given is lower-case
 			 if(Character.isLowerCase(theChar))
 			{
-			
+				 // give a the character a position number from the lower-case String
 				 int position = lowerCase.indexOf(theChar);
+				 // Adding the offSet to the position number
 				 int newPosLower = position + theOffset;
+				 // making sure that the alphabet is a continuous cycle.
 				 if(newPosLower > 25)
 				 {
+					 // if the offSet moves it past 'z' then take 26 off newPosLower.
 					 newPosLower -= 26;
 				 }
 				 else if(newPosLower < 0)
 				 {
+					// if the offSet goes back past 'a' then add 26 to newPosLower.
 					 newPosLower += 26;
 				 }
 				 encChar=lowerCase.charAt(newPosLower);
@@ -45,12 +52,15 @@ public class AssessmentPartThree {
 			{
 				 int position = upperCase.indexOf(theChar);
 				 int newPosUpper = position + theOffset;
+				// making sure that the alphabet is a continuous cycle.
 				 if(newPosUpper > 25)
 				 {
+					// if the offSet moves it past 'Z' then take 26 off newPosLower.
 					 newPosUpper -= 26;
 				 }
 				 else if(newPosUpper < 0)
 				 {
+					// if the offSet goes back past 'A' then add 26 to newPosLower.
 					 newPosUpper += 26;
 				 }
 				 encChar=upperCase.charAt(newPosUpper);
@@ -58,6 +68,7 @@ public class AssessmentPartThree {
 				 return encChar;
 			}
 		}
+		 // if letter isn't a character then return original value
 		else
 		{
 			return encChar;
@@ -69,13 +80,19 @@ public class AssessmentPartThree {
 	 
 	 public String encryptedString(String theMessage, int theOffset)
 	 {
-		 // 06 - encryptedMessage
-		 // Complete this method so that it uses encryptedCharacter to 
-		 // return the encrypted version of theMessage using theOffset
+		 /* 06 - encryptedMessage
+		 Complete this method so that it uses encryptedCharacter to 
+		 return the encrypted version of theMessage using theOffset
+	     */
+		 
 		 String encMessage = "";
+		 // turning theMessage into characters
 		 char[] chars = theMessage.toCharArray();
+		 // for loop to go through each char
 		 for(int i = 0; i<chars.length; i++)
 		 {
+			 // using the method above to calculate each character separately 
+			 //then adding them to the String 'encMessage'
 			 encMessage += enryptedCharacter(chars[i], theOffset);
 		 }
 		 return encMessage;