Cast operator

Problem: given int i, access a particular byte

big-endian

little-endian

int i = 0x1234abcd;

Address

Contents

Is this big-endian or little-endian?  How can we tell?

&i

1000

12

cd

By definition, if we look at the bits in i, the leftmost bits are

1001

34

ab

0001

0010

(big- or little-endian)

1002

ab

34

Value is independent of byte order

1003

cd

12

Another way to look at 4 bytes:

1004

char c[4];

1005

What about

1006

c[0] = (char) i;

1007

Doesn't do what we want, because cast converts value

from int to char

What type of value is char really?

Need to look at the individual memory locations as char

How do we refer to memory locations?

int * iptr = &i;

char * byte_ptr = (char *) &i;

Converts pointer, not data

Now we can increment byte_ptr to look at each byte within the int