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Normal year and leap year calculator

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There will be an error message when entering for the first time, and it will disappear when you click the button.

红红火火恍恍惚惚 2019-10-08 00:08:23

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Normal year and leap year calculator

$num1=$_GET['num1'];
if(!is_numeric($num1))
{echo 'Please enter the year correctly';
exit;}
if($num1%4 ==0 and $num1 0!==0 or $num1@0==0)
{echo $num1.

红红火火恍恍惚惚

reply all (2)

海风2019-10-09 11:09:14 2 floor

$_GET['num1'] does not exist when you first enter. It will be an error to assign a non-existent value to a variable, so give $num1 an initial value, such as: $num1 = isset($_GET[' num1']) ? $_GET['num1'] : 2019;

If you don't want the sentence "2019 is a normal year" to appear as soon as you refresh, modify the program as follows:

if (!empty($_GET['num1'])){

$num1=$_GET['num1'];

if(!i

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reply Okay, thank you, boss.

红红火火恍恍惚惚 author 2019-10-09 22:41:12

reply Why does isset report an error and empty does not?

红红火火恍恍惚惚 author 2019-10-09 23:07:47

reply Boss, I just tried it and the conclusion is that when num1 is not empty, execute $num1=$_GET['num1']; If num1 is empty, the code within the curly brackets will not be executed. Is my conclusion correct or wrong?

红红火火恍恍惚惚 author 2019-10-09 23:17:50

reply Check the manual. The empty function determines whether the parameter is empty. If the parameter is empty, the empty function returns true. Therefore, if num1 is empty, empty('num1') returns true, !empty('num1') returns false, so the code within the curly brackets will not be executed.

海风 author 2019-10-10 09:22:57