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HomeBackend DevelopmentPHP Tutorialphp函数参数的问题

最近在看《深入php面向对象,模式与实践》这本书,P97有个案例把我弄糊涂了
案例是一个读写配置文件的工具。

<code>function readParams($sourceFile){
    $params = array();
    //从$sourceFile中读取文本参数,省略代码
    return $params;
}

function writeParams(**$params,$sourceFile**){
    //写入文本参数到$sourceFile,省略代码
}
</code>

然后是客户端的代码

<code>$file = "./params.txt";
$array['key1'] = "val1";
$array['key2'] = "val2";
$array['key3'] = "val3";

**writeParams($array, $file);**//将数组写入文件
$output = readParams($file);//从文件读取数组
print_r($output);
</code>

疑问是writeParams()方法。为什么后面参数写的不一样。我知道writeParams要传的第一个参数是关联数组第二个参数是源文件路径。。但在第一段代码里参数写成writeParams($params,$sourceFile)这是为什么呢。。

回复内容:

最近在看《深入php面向对象,模式与实践》这本书,P97有个案例把我弄糊涂了
案例是一个读写配置文件的工具。

<code>function readParams($sourceFile){
    $params = array();
    //从$sourceFile中读取文本参数,省略代码
    return $params;
}

function writeParams(**$params,$sourceFile**){
    //写入文本参数到$sourceFile,省略代码
}
</code>

然后是客户端的代码

<code>$file = "./params.txt";
$array['key1'] = "val1";
$array['key2'] = "val2";
$array['key3'] = "val3";

**writeParams($array, $file);**//将数组写入文件
$output = readParams($file);//从文件读取数组
print_r($output);
</code>

疑问是writeParams()方法。为什么后面参数写的不一样。我知道writeParams要传的第一个参数是关联数组第二个参数是源文件路径。。但在第一段代码里参数写成writeParams($params,$sourceFile)这是为什么呢。。

有一种东西叫做。。。形参。。。

全称为“形式参数”是在定义函数名和函数体的时候使用的参数,目的是用来接收调用该函数时传递的参数。

在一般传值调用的机制中只能把实参传送给形参,而不能把形参的值反向地传送给实参。因此在函数调用过程中,形参值发生改变,而实参中的值不会变化。而在引用调用的机制当中是将实参引用的地址传递给了形参,所以任何发生在形参上的改变实际上也发生在实参变量上。

《形参》

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