73 lines
2.1 KiB
C
73 lines
2.1 KiB
C
|
#include <stdio.h>
|
||
|
|
#include <stdlib.h>
|
||
|
|
|
||
|
|
union number
|
||
|
|
{
|
||
|
|
double d;
|
||
|
|
float f;
|
||
|
|
long l;
|
||
|
|
int i;
|
||
|
|
unsigned short s;
|
||
|
|
unsigned char c[8];
|
||
|
|
};
|
||
|
|
|
||
|
|
int main(void)
|
||
|
|
{
|
||
|
|
/* Define variables and a union */
|
||
|
|
int my_i;
|
||
|
|
short my_s;
|
||
|
|
unsigned char tc;
|
||
|
|
union number mynum;
|
||
|
|
|
||
|
|
/* Prompt for use input ao a number whose bytes we are to swap */
|
||
|
|
printf ("\nPlease enter a number ");
|
||
|
|
scanf("%hi",&my_s); // hi is the format for a signed short
|
||
|
|
|
||
|
|
/* pop this number into our union */
|
||
|
|
mynum.s = my_s;
|
||
|
|
|
||
|
|
/* Show the present byte order */
|
||
|
|
printf ("\nThe bytes making up your number %hi are ",my_s);
|
||
|
|
printf ("%d %d %d %d %d %d %d %d ",mynum.c[0],mynum.c[1],mynum.c[2],mynum.c[3],mynum.c[4],mynum.c[5],mynum.c[6],mynum.c[7]);
|
||
|
|
|
||
|
|
/* We now swap the two lowest bytes (via an intermediate variable) */
|
||
|
|
tc = mynum.c[1];
|
||
|
|
mynum.c[1] = mynum.c[0];
|
||
|
|
mynum.c[0] = tc;
|
||
|
|
|
||
|
|
printf ("\nThe bytes making up your number are now ");
|
||
|
|
printf ("%d %d %d %d %d %d %d %d ",mynum.c[0],mynum.c[1],mynum.c[2],mynum.c[3],mynum.c[4],mynum.c[5],mynum.c[6],mynum.c[7]);
|
||
|
|
|
||
|
|
printf ("\nWhich corresponds to %d ",mynum.s);
|
||
|
|
|
||
|
|
// Repeat for an integer
|
||
|
|
/* Prompt for use input ao a number whose bytes we are to swap */
|
||
|
|
printf ("\nPlease enter a number [INTEGER] ");
|
||
|
|
scanf("%d",&my_i);
|
||
|
|
|
||
|
|
/* pop this number into our union */
|
||
|
|
mynum.i = my_i;
|
||
|
|
|
||
|
|
/* Show the present byte order */
|
||
|
|
printf ("\nThe bytes making up your number %d are ",my_i);
|
||
|
|
printf ("%d %d %d %d %d %d %d %d ",mynum.c[0],mynum.c[1],mynum.c[2],mynum.c[3],mynum.c[4],mynum.c[5],mynum.c[6],mynum.c[7]);
|
||
|
|
|
||
|
|
/* We now swap the 1st and 4th bytes (via an intermediate variable) */
|
||
|
|
tc = mynum.c[3];
|
||
|
|
mynum.c[3] = mynum.c[0];
|
||
|
|
mynum.c[0] = tc;
|
||
|
|
|
||
|
|
/* We now swap the 1st and 4th bytes (via an intermediate variable) */
|
||
|
|
tc = mynum.c[2];
|
||
|
|
mynum.c[2] = mynum.c[1];
|
||
|
|
mynum.c[1] = tc;
|
||
|
|
|
||
|
|
printf ("\nThe bytes making up your number are now ");
|
||
|
|
printf ("%d %d %d %d %d %d %d %d ",mynum.c[0],mynum.c[1],mynum.c[2],mynum.c[3],mynum.c[4],mynum.c[5],mynum.c[6],mynum.c[7]);
|
||
|
|
|
||
|
|
printf ("\nWhich corresponds to %d ",mynum.i);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
}
|