从结构中访问变量(Accessing variables from a struct)

从结构中访问变量(Accessing variables from a struct)

我们如何访问一个结构的变量？ 我有一个结构：

typedef struct { unsigned short a; unsigned shout b; } Display;

在我的其他课上我有一个方法：

int NewMethod(Display **display) { Display *disp=new Display(); *display = disp; disp->a=11; }

**显示是什么意思？ 要访问已使用过的结构体变量-> ，还有其他方法吗？

How can we access variables of a structure? I have a struct:

typedef struct { unsigned short a; unsigned shout b; } Display;

and in my other class I have a method:

int NewMethod(Display **display) { Display *disp=new Display(); *display = disp; disp->a=11; }

What does **display mean? To access variables of struct I have used ->, are there other methods too?

最满意答案

正如泰勒所说，双星号是“指针指针”，您可以根据需要获得尽可能多的指针级别。

我相信你知道，箭头运算符（ a->b ）是取消引用指针的星号的快捷方式，以及访问字段的点，即

a->b = (*a).b;

括号是必要的，因为点结合更紧密。 对于双星号没有这样的操作符，在访问这些字段之前，必须首先解除引用才能达到所需的级别：

Display **dpl = ...; (*dpl)->a = 42;

要么

(**dpl).a = 42;

As Taylor said, the double asterisk is "pointer to pointer", you can have as many levels of pointers as you need.

As I'm sure you know, the arrow operator (a->b) is a shortcut for the asterisk that dereferences a pointer, and the dot that accesses a field, i.e.

a->b = (*a).b;

The parentheses are necessary since the dot binds tighter. There is no such operator for double asterisks, you have to first de-reference to get to the required level, before accessing the fields:

Display **dpl = ...; (*dpl)->a = 42;

or

(**dpl).a = 42;