How are you getting that to work without a dictionary of the alphabet?

Code: Cpp
char alphaUpper[26] = {"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"};
char alphaLower[26] = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};

then loop through your text using a for loop and check the index position of the found character then switch it with the value three down. If the index is 26 start at position 0 and add 2 so you'd get C/c.