Introduction and classification of PHP process structure

PHP is a language widely used in server-side script programming. Its process structure introduction and classification are one of the foundations for learning PHP. In this article, you will be introduced to PHP's process structure in detail, including sequence structure, selection structure and loop structure, and provide specific code examples for each structure. I hope that through the explanation of this article, readers can better understand the process control structure of PHP and apply it in actual programming.

1. Sequential structure

The sequential structure is the most basic structure in the program. The code is executed in order, without branches and loops. In PHP, the code example of the sequential structure is very simple, as follows:

<?php
echo "这是顺序结构示例";
echo "<br>";
echo "顺序执行的代码1";
echo "<br>";
echo "顺序执行的代码2";
?>

The above code is output in sequence: This is the sequential structure example, sequentially executed code 1, and sequentially executed code 2.

2. Selection structure

The selection structure determines the execution path of the program based on conditional judgment, including if statements, if...else statements, if...elseif...else statements, etc. The following is an example of an if statement:

<?php
$score = 85;
if ($score >= 60) {
    echo "成绩合格";
} else {
    echo "成绩不合格";
}
?>

When the value of $score is 85, the output result is "passed grade"; when the value of $score is 50, the output result is "failed grade" .

3. Loop structure

The loop structure is a commonly used structure in programs, which can repeatedly execute a block of code, including for loop, while loop, do...while loop, etc. Here is an example of a for loop:

<?php
for ($i = 1; $i <= 5; $i++) {
    echo "当前数字为：" . $i . "<br>";
}
?>

The above code will output numbers from 1 to 5, one line for each number.

To sum up, PHP's process structure includes sequence structure, selection structure and loop structure. Through the specific code examples provided in this article, readers can better understand the usage and principles of these constructs. In practical applications, different process structures are reasonably selected according to specific needs to achieve corresponding functions. I hope this article will be helpful to readers when learning and writing PHP code.

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