PHP 5.6.16 is available

# BCMath 任意精度数学

• 简介
• 安装／配置
• 预定义常量
• BC 数学 函数
• bcadd — 2个任意精度数字的加法计算
• bccomp — 比较两个任意精度的数字
• bcdiv — 2个任意精度的数字除法计算
• bcmod — 对一个任意精度数字取模
• bcmul — 2个任意精度数字乘法计算
• bcpow — 任意精度数字的成方
• bcpowmod — Raise an arbitrary precision number to another, reduced by a specified modulus
• bcscale — 设置所有bc数学函数的默认小数点保留位数
• bcsqrt — 任意精度数字的二次方根
• bcsub — 2个任意精度数字的减法

### User Contributed Notes 4 notes

volek at adamv dot cz
10 months ago
``` Note that when you use implementation of factorial that ClaudiuS made, you get results even if you try to calculate factorial of number that you normally can't, e.g. 2.5, -2, etc. Here is safer implementation:<?php/** * Calculates a factorial of given number. * @param string|int \$num * @throws InvalidArgumentException * @return string */function bcfact(\$num){    if (!filter_var(\$num, FILTER_VALIDATE_INT) || \$num <= 0) {        throw new InvalidArgumentException(sprintf('Argument must be natural number, "%s" given.', \$num));    }    for (\$result = '1'; \$num > 0; \$num--) {        \$result = bcmul(\$result, \$num);    }    return \$result;}?> ```
George Lund
1 year ago
``` It's worth noting that this library is named very wrongly.It may be called 'Binary Calculator', but what you're getting is a decimal calculator that can represent base-10 fractions accurately. ```
ClaudiuS
2 years ago
``` Needed to compute some permutations and found the BC extension great but poor on functions, so untill this gets implemented here's the factorial function:<?php/* BC FACTORIAL * n! = n * (n-1) * (n-2) .. 1 [eg. 5! = 5 * 4 * 3 * 2 * 1 = 120] */function bcfact(\$n){    \$factorial=\$n;    while (--\$n>1) \$factorial=bcmul(\$factorial,\$n);    return \$factorial;}print bcfact(50); //30414093201713378043612608166064768844377641568960512000000000000?> ```
Hayley Watson
1 month ago
``` This extension is an interface to the GNU implementation as a library of the Basic Calculator utility by Philip Nelson; hence the name. ```