【PHP学习】函数

来源：互联网发布：centos 安装opera 编辑：程序博客网时间：2024/05/17 22:03

1.创建函数

其实PHP里面对于函数的操作跟C语言类似，只是多加了些功能，这里我就写下多出来的了，没写的照搬C语言就行。
从函数返回多个值

利用list()构造可以很方便地从数组中获取值。比如：

<?php    $colors=array("red","blue","green");    list($red,$blue,$green)=$colors;?>

执行了list()构造后，$red、$blue、$green分别被赋值为red、blue和green。

<?php    function retrieveUserProfile()    {        $user[]="Jason Gilmore";        $user[]="jason@example.com";        $user[]="English";        return $user;    }    list($name,$email,$language)=retrieveUserProfile();echo "Name:$name,email:$email,language:$language";?>

递归函数

这里可能是书本写的不太全，目前不太明白PHP的递归机制，所以可能会查些资料，作为补充。
这是书本上还贷计算器的代码：

<?php     function amortizationTable($pNum,$periodicPayment,$balance,$monthlyInterest)    {        $paymentInterest=round($balance*$monthlyInterest,2);        $paymentPrincipal=round($periodicPayment-$paymentInterest,2);        $newBalance=round($balance-$paymentPrincipal,2);        if($newBalance<$paymentPrincipal){            $newBalance=0;        }        printf("<tr><td>%d</td>",$pNum);        printf("<td>$%s</td>",number_format($newBalance,2));        printf("<td>$%s</td>",number_format($periodicPayment,2));        printf("<td>$%s</td>",number_format($paymentPrincipal,2));        printf("<td>$%s</td></tr>",number_format($paymentInterest,2));        if($newBalance>0){            $pNum++;            amortizationTable($pNum, $periodicPayment, $newBalance, $monthlyInterest);        }        else{            return 0;        }    }    $balance=10000.00;    $interestRate=.0575;    $monthlyInterest=$interestRate/12;    $termLength=5;    $paymentsPerYear=12;    $paymenetNumber=1;    $totalPayments=$termLength+$paymentsPerYear;    $intCalc=1+$interestRate/$paymentsPerYear;    $periodicPayment=$balance*pow($intCalc,$totalPayments)*($intCalc-1)/(pow($intCalc,$totalPayments)-1);    $periodicPayment=round($periodicPayment,2);    echo "<table width='50%' align='center' border='1'>";    echo "<tr>            <th>Payment Number</th><th>Balance</th>            <th>Payment</th><th>Principal</th><th>Interest</th>            </tr>";    amortizationTable($paymenetNumber,$periodicPayment,$balance,$monthlyInterest);    echo "</table>";?>

函数库

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