<?php/*PHP函数在PHP创建用户定义函数用户定义的函数声明以关单“function”开头：语法：function functionName() {被执行的代码;}注释：函数名能够以字母或下划线开头(而非数字)注释：函数对大小写不敏感提示：函数名应该能够反映函数所执行的任务*/function writeMsg() {echo "Hello world!";}writeMsg();//调用函数echo "<br>";echo "--------------";echo "<br>";/*PHP函数参数可以通过参数向函数传递信息。*/function familyName($fname) {echo "$fname Zhang.<br>";}familyName("Li");familyName("Hong");familyName("Tao");familyName("Xiao Mei");familyName("Jian");echo "<br>";echo "--------------";echo "<br>";function familyName2($fname, $year) {echo "$fname Zhang. Born in $year <br>";}familyName2("Li", "1975");familyName2("Hong", "1978");familyName2("Tao", "1983");echo "<br>";echo "--------------";echo "<br>";/*PHP默认参数值*/function setHeight($minheight = 50) {echo "The height is $minheight <br>";}setHeight(350);setHeight();//将使用默认值setHeight(136);setHeight(80);echo "<br>";echo "--------------";echo "<br>";/*PHP函数 - 返回值*/function sum($x, $y) {$z = $x + $y;return $z;}echo "5 + 10 = " . sum(5, 10) . "<br>";echo "7 + 13 = " . sum(7, 13) . "<br>";echo "2 + 4 = " . sum(2, 4);?>
返回结果：
PHP 函数
原文地址：https://www.cnblogs.com/xsr7yer/p/9042631.html