除法不输出正确答案C ++ [英] Division not outputting correct answer c++

问题描述

我是C语言的新手，我正在尝试编写一个基本的数学程序来适应这种语言.当我尝试将问题9/2或任何带有小数的问题解答时，答案似乎是错误的.我想要一个"4.50"的输出，但是我继续得到"4.00".是什么原因引起的，以及如何预防.谢谢

I'm new to c++ and I'm trying to make a basic math program to get warmed up to the language.when I try to do the problem 9/2 or anything with a decimal the answer seems to be wrong. I would like an output of "4.50" but I keep on getting "4.00". What causes this and how do I prevent it. thanks

double INN = 0.0;   
INN = 9 / 2;
std::cout.precision (3);
std::cout << std::showpoint << INN << endl;

推荐答案

INN = 9/2; 将 4.0 分配给 INN .

将其替换为 INN = 9.0/2.0; 以分配 4.5 .

说明:

因为 9 和 2 都是整数，所以 9/2 总是产生整数除法，其结果也是整数.因此，结果必须四舍五入，并四舍五入到最接近的整数.

Because both 9 and 2 are integers, 9 / 2 always results in an integer division, the result of which is an integer too. Thus the result must be rounded, and is rounded down to the nearest integer.

9.0 和 2.0 是双精度的，因此 9.0/2.0 将导致浮点除法，从而导致双精度值.

Whereas 9.0 and 2.0 are doubles, thus 9.0 / 2.0 will result in a floating point division, which results in a double value.

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