12:08 03/12/18

src/AssessmentPartThree.java

@@ -8,25 +8,56 @@ public class AssessmentPartThree {
 	// - 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
-		 
-		 return 'a';
-	 }
+	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
+	  
+	//Uppercase characters
+	if((theChar >= 65) && (theChar <= 90)) //65 to 90 = A to B
+	{
+	theChar = (char) (((theChar - 65 + theOffset) % 26) + 65);
+	}
+	//Lowercase characters
+	else if((theChar >= 97) && (theChar <= 122)) // 97 to 122 = a to b
+	{
+	theChar = (char) (((theChar - 97 + theOffset) % 26) + 97);
+	}
+	/*
+	theChar = (char) (((theChar - 97 + theOffset) % 26) + 97); formulae
+	                      (theChar - 97 - ASCII a/A to give value between 1 and 26  
+	            + theOffset) + the offset value
+	                      (                           % 26) % modulo ensures value is always between 1 and 26
+	                    (                                  + 97) + ASCII a/A to return result to ASCII char
+	              (char) result needs to be casted to char 
+	*/
+	return theChar;
+	}
+
+	 
+	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
+	 
+	char chaMessageArr[] = theMessage.toCharArray();
+	char[] chaResultArr = new char[chaMessageArr.length];
+	//initialising Arrays
+	  
+	for(int i = 0; i < chaMessageArr.length; i++)
+	//loop to run through each character in encrypted message
+	{
+	chaResultArr[i] = enryptedCharacter(chaMessageArr[i], theOffset);
+	//passing each character to decryption method and saving result in array
+	}
 	 
-	 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
-		 
-		 return "Encryptred message";
-	 }
+	return (new String(chaResultArr));
+	//converting result array into string, and returning this
+	}
 	
 }