int vs NSNumber vs NSInteger [英] int vs NSNumber vs NSInteger

问题描述

我有一行代码将根据数据类型day和1的不同而有所不同。我相信以下内容虽然我稍后会检查我的源代码。

I have a line of code that will work differently depending on the datatypes "day" and "1". I believe it is the following although I will check my source code later.

day = day + 1;

这有意义吗？差异会是什么？

Does this make sense? What would the differences be?

推荐答案

NSInteger 是一个类型定义，描述一个整数 - 但它不等同于64位平台上的 int 。

您可以通过cmd单击<$ c来检查typedef Xcode中的$ c> NSInteger 。

NSInteger 定义为 int 构建32位应用程序时和64位应用程序的 long 。

大多数情况下你可以用NSInteger替换int，但是这样做有一些事情要考虑。

Apple的64位Cocoa过渡指南提供了一些相关信息。

NSInteger is a type definition that describes an integer - but it is NOT equivalent to int on 64-bit platforms.
You can examine the typedef by cmd-clicking on NSInteger in Xcode.
NSInteger is defined as int when building a 32-bit app and as long for 64-bit apps.
Most of the time you can replace int with NSInteger, but there are some things to consider when doing so.
Apple's 64-Bit Transition Guide for Cocoa has some information about that.

NSNumber 是一个帮助您将数字类型存储为对象的类。它具有在不同类型和方法之间进行转换的方法，以检索数值的字符串表示。

如果使用类型<$的变量 day c $ c> NSNumber * 您在示例中所做的方式，您没有修改 day 的值，而是修改其内存地址。

NSNumber is a class that helps you to store numeric types as object. It has methods to convert between different types and methods to retrieve a string representation of your numeric value.
If you use a variable day of type NSNumber* the way you did in your example, you are not modifying the value of day but its memory address.

如果您正在处理时间值，您还可以查看 NSDate 。

If you are working with time values you also could take a look at NSDate.

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