飞镖错误计算总和

Question

有人可以向我解释为什么以下总和在 dart 中给出错误的结果吗？

final double result = 90071992547409.9 + 0.01;
print(result);

它打印数字 90071992547409.92

Answer 1

根据Dart documentation：

Dart doubles are 64-bit floating-point numbers as specified in the IEEE 754 standard.

因为floating-point arithmetic. In your case (I used this converter):

90071992547409.9 = 90071992547409.90625 ~= 90071992547409.91

0.01 = 0.01000000000000000020816681711721685132943093776702880859375 ~= 0.01

90071992547409.91 + 0.01 = 90071992547409.92

dart 中最好的解决方案是使用 decimal 包。