为何将int除以2会产生正确的值？ [英] Why does dividing two int not yield the right value when assigned to double?

问题描述

下面的代码片段中的结果

How come that in the following snippet

int a = 7;
int b = 3;
double c = 0;
c = a / b;

c 最终具有值2，而不是人们所期望的2.3333。如果 a 和 b 是双打，答案的确变为2.333。但是可以肯定的是，由于 c 已经是双精度数，它应该使用整数吗？

c ends up having the value 2, rather than 2.3333, as one would expect. If a and b are doubles, the answer does turn to 2.333. But surely because c already is a double it should have worked with integers?

那么 int / int = double 不起作用？

推荐答案

这是因为您正在使用 operator / 的整数除法版本，它需要2个 int s并返回 int 。为了使用 double 版本，该版本将返回 double ，其中至少一个 int 必须显式转换为 double 。

This is because you are using the integer division version of operator/, which takes 2 ints and returns an int. In order to use the double version, which returns a double, at least one of the ints must be explicitly casted to a double.

c = a/(double)b;

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