/* endian.c
   Franek demonstration of endianness (CS 32 Reader p. 386) */
#include <stdio.h>

char* Bits(char c);
int AmBigEndian();

   /* create a segment of static memory with the right data */
   char a[4] = {'A','B','C','D'}; 


/* function main ------------------------------------------- */
int main()
{
   char* b = a;            /* b points to the beginning of a */
   short* s = (short*) a;  /* s points to the beginning of a */
   int* p = (int*) a;      /* p points to the beginning of a */
   float* f = (float*) a;  /* f points to the beginning of a */

   if (AmBigEndian())
     printf("I am big endian\n");
   else
     printf("I am little endian\n");

   /* show the data as 4 characters */
   printf("'%c','%c','%c','%c'\n",*b,*(b+1),*(b+2),*(b+3));
   printf("%s ",Bits(a[0]));
   printf("%s ",Bits(a[1]));
   printf("%s ",Bits(a[2]));
   printf("%s ",Bits(a[3]));
   putchar('\n');

   /* show the data as 2 short integers */
   printf("%d,%d\n",*s,*(s+1));
 
   /* show the data as 1 integer */
   printf("%d\n",*p);
 
   /* show the data as 1 float */
   printf("%f\n",*f);

   return 0;

}/*end main*/



/* function Bits ---------------------------------------------- */
char* Bits(char c)
{
   static char ret[9];
   int i;
 
   i = (int) c;
   if (!AmBigEndian()) i = i >> 24;
  
   ret[0]=((c&128)==128)+'0';
   ret[1]=((c&64)==64)+'0';
   ret[2]=((c&32)==32)+'0';
   ret[3]=((c&16)==16)+'0';
   ret[4]=((c&8)==8)+'0';
   ret[5]=((c&4)==4)+'0';
   ret[6]=((c&2)==2)+'0';
   ret[7]=((c&1)==1)+'0';
   ret[8]='\0';
  
   return ret;
}/* end Bits */



/* function AmBigEndian -------------------------------- */
int AmBigEndian()
{
  long x = 1;
  return !(*((char *)(&x)));
}/* end AmBigEndian */