Replace - TryCrack.Me PHP Code Review Challange Walkthrough

Let’s dive into a PHP code review challenge from TryCrack.ME and elevate our skills stats.

• The purpose of this review is to go through the PHP code provided for the Replace challenge from TryCrack.Me and to solve the challenge effectively. We will break down the code, understand its functionality, and then proceed with solving the problem.

Here is Our Code…..

$your_input = "";

$txt = str_replace("op","",$your_input);

if($txt === "reprop")
  echo ("Good job!");
else
  echo ("Wrong Answer!");  

This PHP code review challenge involves manipulating the input string and performing a conditional check based on the string transformation. Let’s go step by step to understand what the code is doing.

What Does Code Says………

1 . Initializing$your_input**:

$your_input = "";

• The variable $your_input is initialized as an empty string, but it will hold the input given by the user.
• For this challenge, the user would typically provide some input here.

2 . Using str_replace():

$txt = str_replace("op", "", $your_input);

• str_replace(): This PHP function replaces all occurrences of a substring within a string.
  • In this case, the substring "op" is being replaced with an empty string "".
  • The result of this replacement is stored in the variable $txt.

3 . The if Condition

if($txt === "reprop")

• After modifying $your_input with str_replace(), the code checks whether the resulting string $txt is exactly equal to "reprop".
• exactly equal to operator is the strict equality operator, which checks both value and type. In this case, the check is for an exact match of the string "reprop".

1. Output:

echo ("Good job!");

• If the modified input $txt matches the string "reprop", the message "Good job!" is displayed.

echo ("Wrong Answer!");

• If the modified input $txt does not match "reprop", the message "Wrong Answer!" is displayed.

Key Point :

• The transformation involves removing all occurrences of "op" from the input string. The challenge requires the user to input a string that, after removing "op", results in "reprop".

  Walkthrough:

• Let’s find the original input that results in "reprop" after removing "op".

  1. The code expects the output $txt to be "reprop".
  2. Adding "op" at strategic places in "reprop" should give us the input that will pass the condition.

  If we insert "op" back into "reprop", we get "reproopp".

  So, the correct input for this challenge would be:

$your_input = "reproopp";

Explanation of Input:

• If you input "reproopp", the str_replace() function will remove the "op" substrings:
  • str_replace("op", "", "reproopp") results in "reprop".
  • Since this matches the expected value in the if condition, the script will output "Good job!".

Summary :

• The challenge involves providing an input where, after removing "op", the string becomes "reprop".
• The correct input to pass the challenge is "reproopp".

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