比较php7与php 5.5 运行效率

<?php
$stratTime   = microtime(true);
$startMemory = memory_get_usage();
$a = 1;for($i = 1; $i <= 100000; $i++){
	$a++;}echo $a;$endTime    = microtime(true);$runtime    
	= ($endTime - $stratTime) * 1000; 
	//将时间转换为毫秒$endMemory  = memory_get_usage();
	$usedMemory = ($endMemory - $startMemory) / 1024;echo "运行时间: {$runtime} 毫秒<br />";echo "耗费内存: {$usedMemory} K";

100001运行时间: 3 - 7 毫秒耗费内存: 0.109375 K

100001运行时间: 18 - 30 毫秒耗费内存: 0.671875 K