C ++变量declation语法 [英] C++ variable declation syntax

问题描述

我最近遇到了这个结构：
int（m）;
这似乎等价于：
int m;

奇怪的是，我从来没有见过这个特殊的成语。有人可以指点我的参考，我可以阅读这个规范，或只是直接解释？

解决方案

$ b

这不是一个成语。它只是一对冗余的括号。

有时，类似的多余括号可用于解决C ++声明中的歧义，例如

  int a（int（））; 
  

它声明一个函数可以变成

  int a（（int（）））; 
  

相当于

  int a = int（）; 
  

并定义一个变量。但这不是你在你的情况下。

I recently came across this construct: int(m); which seems to be equivalent to: int m;

Oddly, I have never seen this particular idiom before. Can someone point me to a reference where I can read the spec on this, or just explain directly? Does this also work in straight C?

Thanks, ConfusedDeveloper

解决方案

It is not an "idiom". It is just a redundant pair of parentheses. Grammatically, they can be there, but they serve no purpose.

Sometimes similar seemingly superfluous parentheses can be used to resolve ambiguity in C++ declarations, like

int a(int());

which declares a function can be turned into

int a((int()));

which is equivalent to

int a = int();

and defines a variable. But this is not exactly what you have in your case.

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