C - Find the size of structure

Question

I was asked this as interview question. Couldn\'t answer.

Write a C program to find size of structure without using the sizeof operator.

Answer 1

Here's another approach. It also isn't completely defined but will still work on most systems.

typedef struct{
    //  stuff
} mystruct;

int main(){
    mystruct x;
    mystruct *p = &x;

    int size = (char*)(p + 1) - (char*)p;
    printf("Size = %d\n",size);

    return 0;
}