的C条件运算符（“？”）空第二个参数 [英] C conditional operator ('?') with empty second parameter

问题描述

典型地，？运营商在以下形式使用：

Typically the '?' operator is used in the following form:

A ? B : C

然而在B = A我看到以下简称案件

However in cases where B = A I have seen the following abbreviation

A ? : C

这令人惊讶的作品。它是更好地留在第二个参数（风格明智），或者是他们的一个机会，一定编译器将无法处理呢？

This surprisingly works. Is it better to leave the second parameter in (style wise), or is their a chance certain compilers won't be able to handle this?

推荐答案

这不是由C语言允许（据我所知），但编译器，如GCC有快捷方式：C为的扩展。
A：C 意思是一样的 A一：C

It is not permitted by the language C (as far as I know), but compilers such as gcc have the shortcut a?:c as an extension. a?:c means the same as a?a:c.

这篇关于的C条件运算符（“？”）空第二个参数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！