result += chr((ord(char) + s - 97) % 26 + 97) code example

Example: python caesar cipher

def caesar_encrypt():
    word = input('Enter the plain text: ')
    c = ''
    for i in word:
        if (i == ' '):
            c += ' '
        else:
            c += (chr(ord(i) + 3))
    return c

def caesar_decrypt():
    word = input('Enter the cipher text: ')
    c = ''
    for i in word:
        if (i == ' '):
            c += ' '
        else:
            c += (chr(ord(i) - 3))
    return c
  
plain = 'hello'
cipher = caesar_encrypt(plain)
decipher = caesar_decrypt(cipher)