C语言 用整数除以双精度
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Dividing a double with integer
提问by hardcoder
I am facing an issue while dividing a doublewith an int. Code snippet is :
我在将 adouble与int. 代码片段是：
double db = 10;
int fac = 100;
double res = db / fac;
The value of res is 0.10000000000000001instead of 0.10.
res 的值是0.10000000000000001代替0.10。
Does anyone know what is the reason for this? I am using cc to compile the code.
有谁知道这是什么原因？我正在使用 cc 来编译代码。
回答by sml
You need to read the classic paper What Every Computer Scientist Should Know About Floating-Point Arithmetic.
您需要阅读经典论文What Every Computer Scientist should Know About Floating-Point Arithmetic。
回答by Rotsor
The CPU uses binary representation of numbers. Your result cannot be represented exactly in binary. 0.1 in binary is 0.00011001100110011... CPU truncates it at a certain point and gets some rounding error.
CPU 使用数字的二进制表示。您的结果不能完全以二进制表示。二进制的 0.1 是 0.00011001100110011... CPU 在某个点截断它并得到一些舍入错误。
回答by Meiscooldude
double is a floating point operator, they do not provide precise values. Look up Precision and Floating Point Operators on google.
double 是浮点运算符，它们不提供精确值。在谷歌上查找精度和浮点运算符。
