p "================Palindrome string ?================"

def is_palindrome(str)
    str = str.gsub(/[^A-Za-z0-9]/, '').downcase

    puts (str.size/2).times.all?{|x| str[x] == str[-x-1]}
end

is_palindrome("A Man, A Plan, A Canal, Panama!")

is_palindrome("Ring fo King")


def check_palindrome(str)
    formatted_string = str.gsub(/[^A-Za-z0-9]/, '').downcase
    reversed_arr = []
    arr = formatted_string.split("")

    (arr.length-1).downto(0){|i| reversed_arr.push(arr[i])}

    formatted_string == reversed_arr.join('')
end

p check_palindrome("A man, A Plan, A canal, Panama!")

p check_palindrome("Ring fo King")


def palindrome?(str)
    is_palindrome = false
    formatted_str = str.gsub(/[^A-Za-z0-9]/, '').downcase
    (formatted_str.length/2).times{|x| is_palindrome = true if formatted_str[x] == formatted_str[-x-1]}
    is_palindrome
end

p palindrome?("A man, A Plan, A canal, Panama!")

p "================Reverse a string================"

def reverse_string(str)
    (str.length/2).times{|x| str[x], str[-x-1] = str[-x-1], str[x]}
    str
end

p reverse_string("A man, A Plan, A canal, Panama!")