发布于 2014-11-30 03:16:24 | 142 次阅读 | 评论: 0 | 来源: 网友投递
这里有新鲜出炉的PHP设计模式，程序狗速度看过来！
PHP开源脚本语言
PHP（外文名: Hypertext Preprocessor，中文名：“超文本预处理器”）是一种通用开源脚本语言。语法吸收了C语言、Java和Perl的特点，入门门槛较低，易于学习，使用广泛，主要适用于Web开发领域。PHP的文件后缀名为php。
本文为大家讲解的是了PHP中round()函数对浮点数进行四舍五入的方法及使用示例,通过详尽的实例对round()函数的各种常见用法进行了归纳整理,需要的朋友可以参考下
语法:round(x,prec)
| 参数 |
描述 |
| x |
可选,规定要舍入的数字. |
| prec |
可选,规定小数点后的位数. |
说明:返回将 x 根据指定精度 prec(十进制小数点后数字的数目)进行四舍五入的结果,prec 也可以是负数或零(默认值).
提示和注释
注释:php默认不能正确处理类似 "12,300.2" 的字符串.
注释:prec 参数是在 php 4 中被引入的,实例代码如下:
<?php
*/
echo round(3.4); //输出3
echo "<br>";
echo round(3.5); //输出4
echo "<br>";
echo round(3.6); //输出4
echo "<br>";
echo round(3.6,0); //输出4
echo "<br>";
echo round(1.95583,2); //输出1.96
echo "<br>";
echo round(1241757,-3); //输出1242000
echo "<br>";
echo round(4.045,2); //输出4.05
echo "<br>";
echo round(4.055,2); //输出4.06
//使用stdround函数代替php的round函数
?>
<?php
function stdround($num, $d=0)
{
return round($num + 0.0001 / pow(10, $d), $d);
}
echo "round(1.005,2)= ".round(1.005,2). "n ";
echo "round(1.015,2)= ".round(1.015,2). "n ";
echo "round(1.025,2)= ".round(1.025,2). "n ";
echo "round(1.035,2)= ".round(1.035,2). "n ";
echo "round(1.045,2)= ".round(1.045,2). "n ";
echo "round(1.055,2)= ".round(1.055,2). "n ";
echo "round(1.065,2)= ".round(1.065,2). "n ";
echo "round(1.075,2)= ".round(1.075,2). "n ";
echo "round(1.085,2)= ".round(1.085,2). "n ";
echo "round(1.095,2)= ".round(1.095,2). "n ";
echo "stdround(1.005,2)= ".stdround(1.005,2). "n ";
echo "stdround(1.015,2)= ".stdround(1.015,2). "n ";
echo "stdround(1.025,2)= ".stdround(1.025,2). "n ";
echo "stdround(1.035,2)= ".stdround(1.035,2). "n ";
echo "stdround(1.045,2)= ".stdround(1.045,2). "n ";
echo "stdround(1.055,2)= ".stdround(1.055,2). "n ";
echo "stdround(1.065,2)= ".stdround(1.065,2). "n ";
echo "stdround(1.075,2)= ".stdround(1.075,2). "n ";
echo "stdround(1.085,2)= ".stdround(1.085,2). "n ";
echo "stdround(1.095,2)= ".stdround(1.095,2). "n ";
$m=0.000000000000001;
echo "n ";
echo "round(1.005+{$m},2)= ".round(1.005+$m,2). "n ";
echo "round(1.015+{$m},2)= ".round(1.015+$m,2). "n ";
echo "round(1.025+{$m},2)= ".round(1.025+$m,2). "n ";
echo "round(1.035+{$m},2)= ".round(1.035+$m,2). "n ";
echo "round(1.045+{$m},2)= ".round(1.045+$m,2). "n ";
echo "round(1.055+{$m},2)= ".round(1.055+$m,2). "n ";
echo "round(1.065+{$m},2)= ".round(1.065+$m,2). "n ";
echo "round(1.075+{$m},2)= ".round(1.075+$m,2). "n ";
echo "round(1.085+{$m},2)= ".round(1.085+$m,2). "n ";
echo "round(1.095+{$m},2)= ".round(1.095+$m,2). "n ";
echo "round(1.005,2)= ".round(1.005,2). "n ";
echo "round(1.015,2)= ".round(1.015,2). "n ";
echo "round(1.025,2)= ".round(1.025,2). "n ";
echo "round(1.035,2)= ".round(1.035,2). "n ";
echo "round(1.045,2)= ".round(1.045,2). "n ";
echo "round(1.055,2)= ".round(1.055,2). "n ";
echo "round(1.065,2)= ".round(1.065,2). "n ";
echo "round(1.075,2)= ".round(1.075,2). "n ";
echo "round(1.085,2)= ".round(1.085,2). "n ";
echo "round(1.095,2)= ".round(1.095,2). "n ";
?>
参考：php四舍五入函数(floor、ceil、round与intval)