Due to the accuracy of PHP floating point calculations, the order amount is often less than 1 cent.

Due to the accuracy of PHP floating point operations, the order amount is often less than 1 cent.

I recently encountered a strange problem. Orders paid through WeChat in the mall are often less than 1 cent. After troubleshooting, it is caused by the accuracy of PHP floating point operations.

It is caused by the precision of PHP floating point number operations. Brother Niao’s Bolg has detailed instructions. http://www.laruence.com/2013/03/26/2884.html,
When decimals are expressed in binary, 0.58 is an infinite value for binary

0.58的二进制表示基本上(52位)是: 0010100011110101110000101000111101011100001010001111
0.57的二进制表示基本上(52位)是: 0010001111010111000010100011110101110000101000111101

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

0.58 -> 0.57999999999999996
0.57 -> 0.56999999999999995

rrree

Solution:

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