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What is the usage of php do while statement

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Release： 2023-03-12 13:32:02

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php The do while statement will execute the code at least once, and then check the condition. As long as the condition is true, the loop will be repeated; the syntax of the do while statement is "do{code to be executed;}while (condition) ;".

What is the usage of php do while statement

The operating environment of this article: Windows7 system, PHP7.1 version, DELL G3 computer

What is the usage of php do while statement ?

do...while - First execute the block of code once, then repeat the loop when the specified condition is true

do...while statement

The do...while statement will execute the code at least once, then check the condition, and repeat the loop as long as the condition is true.

Syntax

do
{
    要执行的代码;
}
while (条件);

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Example

The following example first sets the value of variable i to 1 ($i=1;).

Then, start the do...while loop. The loop increments the value of variable i by 1 and then outputs. First check the condition (i is less than or equal to 5), as long as i is less than or equal to 5, the loop will continue to run:

<html>
<body>
<?php
$i=1;
do
{
    $i++;
    echo "The number is " . $i . "<br>";
}
while ($i<=5);
?>
</body>
</html>

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Output:

The number is 2
The number is 3
The number is 4
The number is 5
The number is 6

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The do-while loop is very similar to the while loop, the difference is The reason is that the value of the expression is checked at the end of each loop rather than at the beginning. The main difference from a normal while loop is that the do-while loop statement is guaranteed to be executed once (the truth value of the expression is checked after each loop), but in a normal while loop this is not necessarily the case (the truth value of the expression Checked at the beginning of the loop, if it is false at the beginning, the entire loop terminates immediately).

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