Question

1. Consider the two variables in the following C-like (not C) code. Assume that both types of long and int use 32 bits. Do the variable a and b have equivalent type under name type equivalence? What if under structure type equivalence? 0
   
   struct {char c1[4],c1; int i;} a; struct {char c1[2],c2[3]; long l;} b;

Answer 1

Before we jump in, you should know what name and structure equivalence are.
Name equivalence: According to name equialence, two data types are equivalent if the have the same name.
For example:
Let us consider two struct definitions given by you.
struct
{
   char c1[4],c1;
   int i;
}a, c;

struct
{
   char c1[2],c2[3];
   long l;
}b, d;

Here a can be equal to c but not b or d.
Structure equivalence: According to structure equivalence, two data types are equivalent if they have the same structure definition.
Again a and c can be equal because their definitions are one and the same but a and b cannot be equal because their definitions are different.
Here, by definition, I refer to the data members in the struct.