Detailed explanation of 'if...else' statement examples of PHP control statements

I introduced the "if" statement to you before. You know that the "if" statement executes a PHP statement when the expression is satisfied. When the condition is not satisfied, it is not executed. However, in most cases , always execute a PHP statement when the condition is met, and execute other PHP statements when the condition is not met. At this time, you need to use the "if...else" statement we introduce to you today.

Let’s take a look at the syntax format of the "if...else" statement

if(条件表达式){
            PHP语句1;
}else{
            PHP语句2;
}

Detailed explanation of the statement:

Above The meaning of the statement is: when our conditional expression is true, execute PHP statement 1; if the conditional expression is false, execute PHP statement 2. This satisfies the need for PHP statements to be executed when the expression conditions are met, and PHP statements to be executed when the expression conditions are not met.

Let’s take a look at the flow control chart of the “if...else” statement

if...else statement example

This example will be based on "if statement example"," The example of if" statement will have a result output only when the expression is true, otherwise, there will be no output result. But when we use the if...else statement, the result will be output regardless of whether the expression condition is met or not. The code is as follows

<?php
header("content-type:text/html;charset=utf-8");
$num=rand(1,50);
if($num%2==0){
    echo "变量$num 是偶数";
}else{
    echo "变量$num 是奇数";
}
?>

Example explanation:

rand() function The function is to obtain a random integer.

First use the rand() function to generate a number between 1 and 50, and then conditionally determine whether the number is an even number. If it is an even number and the conditional expression is true, then "the variable $num is an even number" is output. , anyway, the conditional expression is false, and "the variable $num is an odd number" is output.

The code running result is as follows:

Because it is randomly generated number, so every time you refresh the page, there will be different results. Give it a try!

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