Conditional Statements in PHP

In PHP, there are three main types of conditional statements: if, else, and elseif. These statements are used to control the flow of a program based on the conditions specified within them.

if statement

1. if statement: The if statement is the simplest type of conditional statement. It allows you to execute a block of code if a certain condition is true. The syntax of an if statement is as follows:

if (condition) {
    // code to be executed if condition is true
}

Example of if statement :

$age = 18;

if ($age >= 18) {
    echo "You are old enough to vote!";
}

In this example, the if statement checks if the $age variable is greater than or equal to 18. If it is, the message "You are old enough to vote!" is echo to the screen.

else statement

2. else statement: The else statement allows you to specify a block of code to be executed if the condition specified in the if statement is false. The syntax of an if-else statement is as follows:

if (condition) {
    // code to be executed if condition is true
} else {
    // code to be executed if condition is false
}

Example of else statement:

$age = 16;

if ($age >= 18) {
    echo "You are old enough to vote!";
} else {
    echo "You are too young to vote.";
}

In this example, the if statement checks if the $age variable is greater than or equal to 18. If it is, the first message is echo. If it's not, the else statement is executed and the second message is echoed instead.

elseif statement

3. elseif statement: The elseif statement allows you to specify multiple conditions to be checked, with a different block of code to be executed for each condition. The syntax of an if-elseif-else statement is as follows:

if (condition1) {
    // code to be executed if condition1 is true
} elseif (condition2) {
    // code to be executed if condition2 is true
} else {
    // code to be executed if all conditions are false
}

Example of elseif statement:

$score = 85;

if ($score >= 90) {
    echo "You got an A!";
} elseif ($score >= 80) {
    echo "You got a B.";
} elseif ($score >= 70) {
    echo "You got a C.";
} else {
    echo "You failed the test.";
}

In this example, the elseif statement checks the value of the $score variable and outputs a different message based on the range it falls into. If $score is greater than or equal to 90, the first message is echo. If it's between 80 and 89, the second message is echoed. If it's between 70 and 79, the third message is echoed. If it's lower than 70, the last message is echo.

These are just a few examples of how conditional statements can be used in PHP. They can be used in a variety of situations to control the flow of a program and make decisions based on specific conditions.

It is important to note that these statements can be nested within each other, allowing for more complex conditional logic to be implemented. Additionally, the ternary operator can be used as a shorthand version of an if-else statement, as follows:

$variable = (condition) ? true : false;

switch (expression) {
    case value1:
        // code to be executed if expression matches value1
        break;
    case value2:
        // code to be executed if expression matches value2
        break;
    // more cases can be added as needed
    default:
        // code to be executed if no case matches expression
        break;
}

$day = "Monday";

switch ($day) {
    case "Monday":
        echo "Today is Monday";
        break;
    case "Tuesday":
        echo "Today is Tuesday";
        break;
    case "Wednesday":
        echo "Today is Wednesday";
        break;
    default:
        echo "It's not Monday, Tuesday, or Wednesday";
        break;
}