如何在C中动态添加结构成员？

Question

struct point { 
    int x;
    int y;
};

main() {
    struct point a;
    a.x = 5;
    a.y = 10;
    printf("%d %d", a.x, a.y);
}

Output:

5 10

Here if I want add a member ( int z ) int the same structure dynamically. What is the procedure?

What I have tried:

struct point {
    int x;
    int y;
};

struct newpoint {
    struct point a;
    int z;
};

I have tried the above steps, through which we have added a new member and the old structure point to new structure newpoint . But this is not what I want, I want to add the new member the same structure dynamically. I got this question in an interview.

Answer 1

The interviewer that asked you this has set you on a trap.

It's impossible to "dynamically define a struct" in C. It's possible to do "duck-typing in other languages, for example JavaScript, but C structures are compile time definitions and are as static as it gets.