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

struct  XYZ{
    int x;
    float y;
    char z;
};

int main(){
    struct XYZ arr[2];
    int sz = (char*)&arr[1] - (char*)&arr[0];
    printf("%d",sz);
    return 0;
}