# Task 2: Reverse Prefix
# Submitted by: Mohammad Sajid Anwar
# 
# You are given a string, $str and a character in the given string, $char.
# Write a script to reverse the prefix upto the first occurrence of the given $char in the given string $str and return the new string.
# 
# Example 1
# Input: $str = "programming", $char = "g"
# Output: "gorpmming"
# 
# Reverse of prefix "prog" is "gorp".
# 
# Example 2
# Input: $str = "hello", $char = "h"
# Output: "hello"
# 
# Example 3
# Input: $str = "abcdefghij", $char = "h"
# Output: "hgfedcbaj"
# 
# Example 4
# Input: $str = "reverse", $char = "s"
# Output: "srevere"
# 
# Example 5
# Input: $str = "perl", $char = "r"
# Output: "repl"

def reverse_prefix(str, char)
    chars = str.split('')
    new_str = ''
    (1..str.length).each do |_|
        letter = chars.shift
        new_str.concat(letter)
        if letter == char
            new_str = new_str.reverse
            break
        end
    end
    new_str.concat(chars.join())

    printf "'%s' '%s' -> '%s'\n", str, char, new_str
end

str = "programming"
char = "g"
reverse_prefix(str, char)

str = "hello"
char = "h"
reverse_prefix(str, char)

str = "abcdefghij"
char = "h"
reverse_prefix(str, char)

str = "reverse"
char = "s"
reverse_prefix(str, char)

str = "perl"
char = "r"
reverse_prefix(str, char)