How PHP handles high-precision computational functions

This article is mainly to share with you how PHP handles high-precision computing functions, the main and we share the two methods, hope to help everyone.

Method 1:

PHP provides a binary calculator (binary Calculator) for any mathematical calculation of arbitrary precision, and it supports numbers of any size and precision, described in string form

bcadd-addition
bccomp-comparison
Divide bcp-
bcmod-seeking remainder
bcmul-multiplication
bcpow-Second Party
bcpowmod-first, then the remainder.
bcscale-Setting the decimal precision for all functions
bcsqrt-the square root
bcsub-Subtraction

Method Two:

Recently encountered a strange problem, the mall through the payment of orders often less than a penny, after the troubleshooting is a problem caused by the accuracy of PHP floating point arithmetic

By the PHP floating-point arithmetic precision caused by, bird Brother's Bolg have detailed description. Http://www.laruence.com/2013/03/26/2884.html,
Decimal in binary notation, 0.58 for binary, is an infinitely long value

The binary representation of 0.58 is basically (52 bits) is: 0010100011110101110000101000111101011100001010001111

The binary representation of 0.57 is basically (52 bits) is: 0010001111010111000010100011110101110000101000111101

Convert to floating point number (64-bit double precision)

0.58-0.57999999999999996

0.57-0.56999999999999995

0.58*100 = 57.999999999 (int) (0.58*100) = 57

Workaround:

(int) ((0.58*1000)/10) = 58

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