多种Ç一行声明 [英] C multiple single line declarations

问题描述

当我宣布说，在一行上多个变量会发生什么？例如。

What happens when I declare say multiple variables on a single line? e.g.

int x, y, z;

所有的都是整数。问题是什么是Y和Z在下面的语句？

All are ints. The question is what are y and z in the following statement?

int* x, y, z;

他们全部诠释指针？

Are they all int pointers?

推荐答案

只有 X 是一个指针为int; 是和以Z 都是正规整数。

Only x is a pointer to int; y and z are regular ints.

这是C的声明语法的一个方面绊倒一些人了。 C使用的不是类型说明符的提供的声明符的，介绍的东西的名字被宣布的以及附加的类型信息的概念。在声明

This is one aspect of C declaration syntax that trips some people up. C uses the concept of a declarator, which introduces the name of the thing being declared along with additional type information not provided by the type specifier. In the declaration

int* x, y, z;

的说明符 * X ，是和以Z （这是，你可以写为为int * X 或为int * X ，而这个C语法的事故问题是几个原因，我建议使用第二种风格）之一。的int-内斯 X ，是和以Z 由类型说明符指定的 INT ，而 X 由声明符指定的<$ C $的指针岬C> * X （IOW，前pression * X 的类型 INT ）。

the declarators are *x, y, and z (it's an accident of C syntax that you can write either int* x or int *x, and this question is one of several reasons why I recommend using the second style). The int-ness of x, y, and z is specified by the type specifier int, while the pointer-ness of x is specified by the declarator *x (IOW, the expression *x has type int).

如果您希望所有三个对象是指针，你有两个选择。您可以声明为指针明确：

If you want all three objects to be pointers, you have two choices. You can either declare them as pointers explicitly:

int *x, *y, *z;

或者您可以创建一个int指针的typedef：

or you can create a typedef for an int pointer:

typedef int *iptr;
iptr x, y, z;

请记住，将指针声明时， * 是变量名称的一部分，而不是类型。

Just remember that when declaring a pointer, the * is part of the variable name, not the type.

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