Classic example of PHP code optimization

When writing PHP code, optimization is an important aspect that improves the performance and maintainability of the code. This article will introduce a classic example showing how to optimize by modifying and polishing the code.

Example: Calculating the Fibonacci Sequence

The Fibonacci sequence is a classic mathematical problem defined as follows: the first and second numbers are 1, and each subsequent number is the sum of the previous two numbers. We will use a recursive function to calculate the Fibonacci sequence and optimize it.

Original code:

function fibonacci($n) {
   
    
    
    if ($n <= 0) {
   
    
    
        return 0;