JNTU MCA 2022 WEB TECHNOLOGIES Previous Question Paper (September/October - 2022 - R20)

PHP control structures allow for flow control within a script, categorized into selection, iteration, and jump statements:

• Selection Statements: These include if, elseif, and else for conditional execution, and the switch statement, which compares a single variable against multiple values.
• Iteration Statements: These are used for looping through code blocks. while and do-while loops execute as long as a condition is true. The for loop is used when the number of iterations is known, and the foreach loop is specifically designed for iterating over arrays and objects.
• Jump Statements: These alter the execution flow. break terminates the current loop or switch, continue skips the remainder of the current loop iteration, and return exits a function or script.

The following script demonstrates a basic credential check using hardcoded values and the header() function for redirection:

<?php
$username = "admin";
$password = "password123";

if ($_POST['user'] == $username && $_POST['pass'] == $password) {
    header("Location: dashboard.php");
    exit();
} else {
    echo "Invalid credentials. Please try again.";
}
?>

In this script, the header() function sends a raw HTTP header to the browser to redirect the user to dashboard.php upon successful verification. The exit() function is essential to ensure no further code is executed after the redirection header is sent.