有负零吗? [英] Is there a negative zero?

问题描述

我正在编写一个简单计算器，只是为了开始使用iPhone开发人员.问题是我有一个(-)按钮，该按钮应该通过执行简单的*-1来抵消已经放置在屏幕上的任何内容.除非上一个输入是0，否则它工作正常.

I'm coding a simple calculator just to get started with iPhone dev. The thing is I have a (-) button thats supposed to negate whatever is put to the screen already by doing a simple *-1. It works fine except when the previous input is 0.

场景:在屏幕为空或0的情况下，我点击(-)取反.然后，当我点击例如9时，我希望它读取(或者更确切地说是 be )-9.现在不是9.仅供参考，我在世界各地的atm都使用原始整数，但是我准备中止它.

Scenario: With empty screen or 0, I tap (-) to negate. Then when I tap for example 9 I want it to read (or rather be) -9. Not 9 as it is now. FYI I'm atm working with primitive ints everywhere but I'm prepared to abort that.

问题:如何表示负数0?我可以使用支持它的数据类型吗? NSInteger?

Questions: How to represent negative 0? Is there a data type I can use that supports it? NSInteger?

或者是使用状态boolean和stringWithFormat等进行某些变通方法的唯一方法吗?

Or is the only way to do some hacky workaround with state boolean and stringWithFormat etc?

感谢帮助. /O

推荐答案

float和double支持-0(如果提供内存，则与0不同).有关更多信息，请参见此处，尽管我不相信使用-0对用户特别有用.您是否有一个需要它的引人注目的用例?

float and double support -0 (which is different than 0 if memory serves). See here for more information, though I'm not convinced using -0 in your application will be particularly helpful for users. Do you have a compelling use case that requires it?

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