为什么将两个 int 分配给 double 时不会产生正确的值?

Why does dividing two int not yield the right value when assigned to double?(为什么将两个 int 分配给 double 时不会产生正确的值?)

问题描述

为什么会出现在下面的代码片段中

How come that in the following snippet

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

c 最终的值为 2，而不是预期的 2.3333.如果 a 和 b 是双精度数，那么答案确实会变成 2.333.但肯定是因为 c 已经是一个 double 它应该与整数一起使用?

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?

那么为什么 int/int=double 不起作用?

So how come int/int=double doesn't work?

推荐答案

这是因为你使用的是整数除法版本的operator/，需要2个ints并返回一个 int.为了使用返回 double 的 double 版本，必须将至少一个 int 显式转换为 双.

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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