Thread: Questions on structure padding

Hi All,

I have following confusion:

1. When the structure is padded?
Eg

Code:

struct A
{
     char c;
};

struct A c;

sizeof(c);

Size of the above struct is one

But

Code:

struct B
{
     int a
     char c;
};

struct B c;

sizeof(c);

Size of the following is 12

How come first structure is not getting padded?

Thanks in advance

The first structure fits perfectly with a C basic data type - a char. No padding needed. The second does not fit perfectly into a basic data type, so it needs it.