java - 2 个双变量乘积的意外结果

Question

这个问题已经有答案了:

Why do I see a double variable initialized to some value like 21.4 as 21.399999618530273? (14 个回答)

Java Double value = 0.01 changes to 0.009999999999999787 [duplicate] (8 个回答)

已关闭 9 年前。

double price = 4.35; 
double quantity = 100; 
double total = price * quantity;   // Should be 100 * 4.35 = 435.00 
System.out.println(total); // Prints 434.99999999999999

为什么会发生这种情况？

Answer 1

乘法工作正常，但 4.35 不能精确地表示为 double 。

检查floating point Internal Representation .

维基百科说:-

The fact that floating-point numbers cannot precisely represent all real numbers, and that floating-point operations cannot precisely represent true arithmetic operations, leads to many surprising situations. This is related to the finite precision with which computers generally represent numbers.