除以零预防 [英] Divide by zero prevention

问题描述

什么是 1.＃INF 和为什么转换到 float 或 double 防止除以0除以崩溃？

此外，任何伟大的想法如何防止除以0？ （像任何宏或模板一样）？

What is 1.#INF and why does casting to a float or double prevent a division by 0 of crashing?
Also, any great ideas of how to prevent division by 0? (Like any macro or template)?

int nQuota = 0;

int nZero = 3 / nQuota; //crash
cout << nZero << endl;

float fZero = 2 / nQuota; //crash
cout << fZero << endl;

如果我改用：

int nZero = 3 / (float)nQuota;
cout << nZero << endl;
//Output = -2147483648

float fZero = 2 / (float)nQuota;
cout << fZero << endl;
//Output = 1.#INF

推荐答案

1.＃INF 是正无穷大。当你将一个正浮点除以零（如果你将浮点零本身除以零，那么结果将是不是一个数字）。你会得到。

1.#INF is positive infinity. You will get it when you divide a positive float by zero (if you divide the float zero itself by zero, then the result will be "not a number").

原因 float fZero = 2 / nQuota;

The reason float fZero = 2 / nQuota; crashes is because both operands of the / operator are integers, so the division is performed on integers. It doesn't matter that you then store the result in a float; C++ has no notion of target typing.

为什么正无穷强制转换为整数是最小的整数，我不知道。

Why positive infinity cast to an integer is the smallest integer, I have no idea.

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