Structure Typecasting

Question

I have a

structure {
    int a;
    char b;
} st;

Is there a way to typecast the structure member st.a? Because in few places I want it as int and in few places I want it as Char*

Answer 1

I suggest to use a union:

struct {
  union {
    int a;
    char *ptr;
  } u;
  char b;
} st;

Under the assumption that sizeof(int) == sizeof(char*) holds, you can access the same value in memory by either using st.u.a or st.u.ptr.

For what it's worth, consider using size_t instead of int as the type of the a field. That way, your code will still be correct in 64bit builds (in which an int may still be 32bit but a pointer is 64bit).

Answer 2

What you want is called unions.