off set in structure or class size.

[engrsanjiv]

How the off set are set while allocating memory.
calss A()
{
public:
char a[10];
char b[2];
float c;
};


calss B()
{
public:
char a[10];
float c;
char b[2];
};

int aa=sizeof(A)// returns 16 bytes
int aa=sizeof(B)// returns 20 bytes

how the offsets are defined in structure and classes.

Thanks.