Detailed explanation of basic syntax of PHP functions and usage examples of passing parameters

The examples in this article describe the function calling and function definition syntax, and explain the variables in the function and the method of passing numerical values ​​to the function. The details are as follows:

1. The basis of functions

php provides a large number of functions and allows users to customize functions.php functionsDefinition example code is as follows :

<?php 
function myCount($inValue1,$inValue2) 
{ 
  $AddValue = $inValue1+$inValue2; 
  
return
 $AddValue;     //返回计算结果 
} 
$Count = myCount(59,100); 
echo $Count;     //输出159 
?>

Once a function is defined, it can be used anywhere.

2. Function parameters

php Function parameters Declare the definition when the function is defined. The function can have any number of parameters. The most commonly used transfer method is to pass by value, or by referencing and default parameter values ​​are relatively rarely used. .The example code is as follows:

<?php 
function myColor ($inColor = "蓝色") 
{ 
    return "我喜欢的颜色： $inColor. "; 
} 
echo myColor(); 
echo myColor("粉色"); 
?>

Generally, the value passed will not be changed due to internal changes in the function, unless it is a global variable or reference. Let’s look at the PHP function reference example. The code is as follows:

<?php 
function str_unite (&$
string
) 
{ 
    $string .= &#39;也喜欢蓝色.&#39;; 
} 
$str = &#39;喜欢红色，&#39;; 
str_unite ($str); 
echo $str;    // 输出结果： &#39;喜欢红色，也喜欢蓝色.&#39; 
?>

Global variables, the code is as follows:

<?php 
$a = 1; 
$b = 2; 
function Sum() 
{
    global $a, $b; 
    $b = $a + $b; 
} 
Sum(); 
echo $b; 
?>

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