Write a program to receive an 8-bit number into a variable and then exchange its higher 4 bits with lower 4 bits.

#include<stdio.h>
#include<conio.h>
#include<windows.h>
#include<math.h>

#define _bv(x) 1<<x
#define _ls(x,y) x<<y
#define _rs(x,y) x>>y

typedef unsigned char Bit;

void bitexchange(Bit*);

int main()
{
	Bit num;
	printf("\nEnter the number : ");
	scanf("%hhd", &num);
	printf("\nBefore shifting\n");
	printf("\nnum : %d", num);
	bitexchange(&num);
	printf("\nAfter exchange");
	printf("\nnum : %d\n", num);
	_getch();
	return 0;
}

void bitexchange(Bit *num)
{
	Bit left, right;
	left = _ls(*num, 4);
	right = _rs(*num, 4);
	*num = 0;
	*num = right | left;
}