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PHP Do-While loop

A PHP do-while loop is a control structure used to repeatedly execute a block of code as long as a specified condition remains true. Unlike the regular while loop, the do-while loop guarantees that the code block will be executed at least once, even if the condition is initially false.

Basic Syntax of Do-While Loop

The basic syntax of "Do-While" Loop in PHP is as follows:

do {
   // Code to be executed at least once
} while (condition);

User Input Validation

$valid = false;
do {
    $userInput = readline("Enter a valid number: ");
    if (is_numeric($userInput)) {
        $valid = true;
    } else {
        echo "Invalid input. Please enter a valid number.\n";
} while (!$valid);

echo "You entered a valid number: " . $userInput;

Rolling a Die until You Get a 6

$roll = 0;

do {
    $roll = rand(1, 6);
    echo "Rolled a $roll.\n";
} while ($roll != 6);

echo "You rolled a 6!";

Calculating the Sum of Numbers from 1 to 10

$n = 1;
$sum = 0;

do {
    $sum += $n;
} while ($n <= 10);

echo "Sum of numbers from 1 to 10: " . $sum;

These examples illustrate how PHP do-while loops work and how they can be used for tasks such as user input validation, simulations, and calculations. The key difference from a regular while loop is that the code block is guaranteed to execute at least once.