Takes an input string and an integer shift factor, performs a Caesar cipher.

caesar_cipher.rb

# Takes an input string and an integer shift factor, performs
# a Caesar cipher.

def caesar_cipher(input,shift_factor)
    message = input.scan(/./)
    cipher = Array.new

    for x in message
    	y = x[0].to_i
    	z = y + shift_factor
    	
    	if y >= 65 && y <= 90
    	    if z < 65 || z > 90
    	        cipher << ((z % 90) + 64).chr
    	    else
    	        cipher << z.chr
    	    end
    	elsif y >= 97 && y <= 122
    	    if z < 97 || z > 122
    	        cipher << ((z % 122) + 96).chr
    	    else
    	        cipher << z.chr
    	    end
        else
            cipher << x[0]
    	end
    end

    return cipher.join
end

# EXAMPLE
puts caesar_cipher("ZzZz",4)

# Caesar cipher shifted 4 results in "DdDd"