在 c 中访问联合成员 [英] access union member in c

问题描述

我有一个关于c语言union的问题

I have a question about union in c language

例如:

typedef struct {
    int a;
     float c;
}Type1;


typedef struct {
    int b;
     char d;
}Type2;

union Select {
    Type1 type1;
    Type2 type2;
};


void main() {
    Select* select;
    //can we access type1 first and then access type2 immediately? like this way:
    select->type1.a;
    select->type2.b;

//访问type1后，立即访问type2，能得到type2的值b吗?//我对第一篇文章做了一点修改，因为开头毫无意义.

//after access type1, and then access type2 immediately, can we get the value b of type2? //I modify the first post a little bit, because it is meanless at the beginning.

}

推荐答案

是的，没错.在您的示例中(忽略未初始化的指针)type1.a 和 type2.b 的值对于任何给定的 Select.

Yes, that is correct. In your example (ignoring the uninitialised pointer) the value of type1.a and type2.b will always be the same for any given instance of Select.

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