The usual techniques are to use a pointer:

int x = 1;

if(*(char *)&x == 1)

printf("little-endiann");

else printf("big-endiann");

or a union:

union {

int i;

char c[sizeof(int)];

} x;

x.i = 1;

if(x.c[0] == 1)

printf("little-endiann");

else printf("big-endiann");

(Note that there are also byte order possibilities beyond simple big-endian and little-endian