为什么我们不能在结构内初始化成员? [英] Why can't we initialize members inside a structure?

问题描述

为什么我们不能在结构内部初始化成员?

Why can't we initialize members inside a structure ?

示例:

struct s {
   int i = 10;
};

推荐答案

如果要在struct 声明中初始化非静态成员:

If you want to initialize non-static members in struct declaration:

在 C++(不是 C)中，structs 几乎是类的同义词，可以在构造函数中初始化成员.

In C++ (not C), structs are almost synonymous to classes and can have members initialized in the constructor.

struct s {
    int i;

    s(): i(10)
    {
    }
};

如果你想初始化一个实例:

在 C 或 C++ 中:

In C or C++:

struct s {
    int i;
};

...

struct s s_instance = { 10 };

C99 还有一个叫做指定初始化器的特性:

C99 also has a feature called designated initializers:

struct s {
    int i;
};

...

struct s s_instance = {
    .i = 10,
};

还有一个 GNU C 扩展，它与 C99 指定的初始化程序非常相似，但最好使用更便携的东西:

There is also a GNU C extension which is very similar to C99 designated initializers, but it's better to use something more portable:

struct s s_instance = {
    i: 10,
};

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