How can using global variables in PHP functions impact code readability and maintainability?

Using global variables in PHP functions can impact code readability and maintainability because it makes it harder to track where and how the variable is being modified throughout the codebase. It can lead to unexpected side effects and make debugging more challenging. Instead of using global variables, it's recommended to pass variables as parameters to functions to make the code more modular and easier to understand. 

// Avoid using global variables in functions
$globalVar = 10;

function incrementGlobalVar() {
    global $globalVar;
    $globalVar++;
}

incrementGlobalVar();
echo $globalVar; // Output: 11

// Better approach: pass variables as parameters
$localVar = 10;

function incrementLocalVar($var) {
    $var++;
    return $var;
}

$localVar = incrementLocalVar($localVar);
echo $localVar; // Output: 11

Keywords

global variables PHP functions code readability maintainability

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