Welcome to the first lesson of this course, where we'll practice the fundamentals of string manipulation in PHP, focusing specifically on scenarios where we refrain from using built-in string functions. Understanding how to navigate and manipulate character strings is an essential skill for software developers. While PHP offers a range of built-in functions to simplify this task, gaining a deeper understanding of how these components work will strengthen your foundation in the language. This knowledge can be particularly beneficial when creating custom solutions or tackling situations where built-in functions are not an option.

In PHP, just like in many programming languages, you can think of a string as an array of individual characters, each with its own index. This allows us to access and manipulate each character independently. For example, to reverse a string, you would typically start from the last character (at an index equal to the length of the string - 1), move towards the beginning, appending each character in reverse order to form a new string. This can be implemented using a for loop, decrementing the index at each step.

Here is how the solution will look in PHP:

php
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1// Reversing a string manually
2function reverseString($originalString) {
3    $reversedString = "";
4    for ($i = strlen($originalString) - 1; $i >= 0; $i--) {
5        $reversedString .= $originalString[$i];
6    }
7    return $reversedString;
8}
9
10$originalString = "hello";
11$result = reverseString($originalString);
12
13echo $result;  // Output: "olleh"

Take your time to digest this concept since it forms the basis of more elaborate tasks that we will encounter later. Once you're ready, let's dive into some hands-on programming exercises that will give you a practical feel for these concepts. Remember, our goal isn't simply to memorize algorithms but to develop an understanding of how to systematically break down and address problems — a skill that is at the heart of programming. As always, practice is your best friend, so let's get coding!