Passing two different structs into same function

Question

I have 2 different sized structs and I would like to have one function in which I can pass them into. However, I do not know how to define the parameter of the function to

Answer 1

Unfortunately, the only choice for unrelated structures in C is to pass pointers to the structures untyped (i.e. as void*), and pass the type "on the side", like this:

struct person1_t {
    int a;             // 2 byte
    int b;             // 2 byte
    int c;             // 2 byte
    int d;             // 2 byte
}  person1;

struct person2_t {
    int a;            // 2 byte
    DeviceAddress b;  // 8 bytes
    int c             // 2 bytes
    float d;      // 4 bytes
}  person2;

void print_struct(void* ptr, int structKind) {
    switch (structKind) {
        case 1:
            struct person1 *p1 = (struct person1_t*)ptr;
            // Print p1->a, p1->b, and so on
            break;
        case 2:
            struct person2 *p2 = (struct person2_t*)ptr;
            // Print p2->a, p2->b, and so on
            break;
    }
}

print_struct(&person1, 1);
print_struct(&person2, 2);

This approach is highly error-prone, though, because the compiler cannot do type checking for you.