PHP中round()函数对浮点数进行四舍五入的方法
本文实例讲述了PHP中round()函数对浮点数进行四舍五入的方法。分享给大家供大家参考。具体方法如下：
语法:round(x,prec)
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php4中被引入的,实例代码如下:
<?php */ echoround(3.4); //输出3 echo"<br>"; echoround(3.5); //输出4 echo"<br>"; echoround(3.6); //输出4 echo"<br>"; echoround(3.6,0); //输出4 echo"<br>"; echoround(1.95583,2); //输出1.96 echo"<br>"; echoround(1241757,-3); //输出1242000 echo"<br>"; echoround(4.045,2); //输出4.05 echo"<br>"; echoround(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";
?>
希望本文所述对大家的PHP程序设计有所帮助。