PHP if, else, and else if Control Stucture

The PHP language provides several control structures to execute different blocks of code based on specific conditions. Among these control structures, the if, else, and elseif statements are used for conditional branching. In this response, I’ll explain the if, else, and elseif control structures in PHP in detail, providing examples to illustrate their usage.

  1. The if statement: The if statement allows you to execute a block of code only if a specified condition evaluates to true. The basic syntax is as follows:
if (condition) {
    // Code to be executed if the condition is true
}

Here’s an example that demonstrates the if statement:

$age = 25;

if ($age >= 18) {
    echo "You are an adult.";
}

In the above example, if the variable $age is equal to or greater than 18, the message “You are an adult.” will be displayed.

  1. The else statement: The else statement is used in conjunction with the if statement to execute a block of code when the condition of the if statement evaluates to false. The syntax is as follows:
if (condition) {
    // Code to be executed if the condition is true
} else {
    // Code to be executed if the condition is false
}

Here’s an example that includes the else statement:

$age = 15;

if ($age >= 18) {
    echo "You are an adult.";
} else {
    echo "You are not yet an adult.";
}

In the above example, if the value of $age is less than 18, the message “You are not yet an adult.” will be displayed.

  1. The elseif statement: The elseif statement allows you to check additional conditions after an initial if statement. It provides an alternative block of code to be executed if the previous if statement condition evaluates to false. The syntax is as follows:
if (condition1) {
    // Code to be executed if condition1 is true
} elseif (condition2) {
    // Code to be executed if condition1 is false and condition2 is true
} else {
    // Code to be executed if both condition1 and condition2 are false
}

Here’s an example that demonstrates the elseif statement:

$age = 25;

if ($age < 18) {
    echo "You are a minor.";
} elseif ($age >= 18 && $age < 65) {
    echo "You are an adult.";
} else {
    echo "You are a senior citizen.";
}

In the above example, if the value of $age is less than 18, the message “You are a minor.” will be displayed. If the age is between 18 and 64, the message “You are an adult.” will be displayed. Otherwise, if the age is 65 or above, the message “You are a senior citizen.” will be displayed.

These examples showcase how the if, else, and elseif control structures can be used to execute different blocks of code based on specified conditions. By utilizing these control structures effectively, you can create dynamic and responsive PHP programs that handle varying scenarios and make decisions based on specific conditions.