PHP Custom Function Learning Notes implementation 99 multiplication table

Using a custom function method to implement the 99 multiplication table, a function is a block of code that can be executed whenever it is needed.

To create a PHP function:
All functions start with the keyword "function ()".
Named function – the name of the function should indicate its function. The function name begins with a letter or an underscore.
Add "{" – the part that follows the curly braces of the opening is the code for the function.
Insert Function code
Add a "}" – The function ends by closing the curly braces.
Example
A simple function that outputs my name when it is invoked:

The code is as follows	Copy Code
<body> <?php function Writemyname () { echo "David Yang"; } Writemyname (); ?> </body>

Using PHP functions
Now we're going to use this function in the PHP script:

The code is as follows	Copy Code
<body> <?php function Writemyname () { echo "David Yang"; } echo "Hello world!<br/>"; echo "My name is"; Writemyname (); echo ". <br/>that ' s right,"; Writemyname (); echo "is my name."; ?> </body> The output of the above code: Hello world! My name is David Yang. That's right, the David Yang was my name

Let's write a function to implement the 99 multiplication table

The code is as follows

Copy Code

<php? /** * 9*9 Multiplication table * String fun_99 (int $start =1, int $end =1,bool $sort =true) * $start starting number must be between 1-9 and must be an integer * $end End value must be between 1-9 and must be an integer and greater than $start * $sort for sorting, true for positive order, false for reverse */ echo " function fun_99 ($start =1, $end =9, $sort =true) { if ($start <1| | $start >9) { Return ' starting number must be between 1-9 '; } if ($end <1| | $end >9) { Return ' end value must be between 1-9 '; } if ($start!= (int) ($start)) { Return ' Starting number must be an integer '; } if ($end!= (int) ($end)) { Return ' end value must be an integer '; } if ($start > $end) { Return ' starting number must be less than the end value '; } $str = '; if ($sort) { for ($i = $start; $i <= $end; $i + +) { $str = $str. " <br> "; for ($n = $start; $n <= $end; $n + +) { if ($i >= $n) { $str = $str. " $i * $n ". = '. $i * $n. " &AMP;NBSP "; } } } }else{ for ($i = $end; $i >= $start; $i-) { $str = $str. " <br> "; for ($n = $end; $n >= $start; $n-) { if ($i >= $n) { $str = $str. " $i * $n ". = '. $i * $n. " &AMP;NBSP "; } } } } return $str; } echo fun_99 (1,9,true); ?>

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