Switch-Case 语句和数字范围 [英] Switch-Case Statement and Range of Numbers

问题描述

有没有办法在 Objective C(在 XCode 中)中使用带有范围的 switch 语句，假设是这样的:

Is there a way to use switch statement with ranges in Objective C (in XCode), hypothetically something like this:

- (NSString *)evaluate:(NSInteger)sampleSize
{
       NSString returnStr;
       switch (sampleSize)
           {
               case sampleSize < 10: 
               returnStr = @"too small!";
               break;

               case sampleSize >11 && sampleSize <50:
               returnStr = @"appropriate";
               break;

               case sampleSize >50:
               returnStr = @"too big!";
               break;
           }
       return returnStr;
}

推荐答案

有一个 GCC 扩展(我假设 Clang 支持它)可能适合您.它允许您在 case 语句中使用范围.完整文档位于 http://gcc.gnu.org/onlinedocs/gcc-4.2.4/gcc/Case-Ranges.html#Case-Ranges - 来自该页面的示例 case 语句是

There is a GCC extension (which I assume is supported in Clang) that might be suitable for you. It allows you to use ranges in case statements. The full documentation is at http://gcc.gnu.org/onlinedocs/gcc-4.2.4/gcc/Case-Ranges.html#Case-Ranges - an example case statement from that page is

case 1 ... 5:

这将匹配(不出所料)1、2、3、4 或 5.

which would match (unsurprisingly) 1, 2, 3, 4, or 5.

这篇关于Switch-Case 语句和数字范围的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！