Swapping bits of an Integer

Swapping individual bits is implemented using a function. This function is repeatedly called with different position data.

	typedef unsigned int uint;
	uint swapBits(uint x, uint i, uint j) {
	uint lo = ((x >> i) & 1);
	uint hi = ((x >> j) & 1);
	if (lo ^ hi) {
	x ^= ((1U << i) | (1U << j));
	}
	return x;
	}
	uint reverseXor(uint x) {
	uint n = sizeof(x) * 8;
	for (uint i = 0; i < n/2; i++) {
	x = swapBits(x, i, n-i-1);
	}
	return x;
	}

view raw SwapBits.c hosted with ❤ by GitHub

Printing the binary format of a integer

Here printing iss done thru a neat macro trick. We can calculate different way too, which is commonly seen. In that case we divide the number by 2 and not the modulo and append it to a string. Same time we will divide the number by two and make it as the new number. This process continues till the number becomes equivalent to one.

	/*
	* printbinary.c
	*
	* Created on: Mar 11, 2015
	* Author: prasadnair
	*/
	/*
	* printBinary.cpp
	*
	* Created on: Mar 11, 2015
	* Author: prasadnair
	*/
	#include <stdio.h>
	#define BYTETOBINARYPATTERN "%d%d%d%d%d%d%d%d"
	#define BYTETOBINARY(byte) \
	(byte & 0x80 ? 1 : 0), \
	(byte & 0x40 ? 1 : 0), \
	(byte & 0x20 ? 1 : 0), \
	(byte & 0x10 ? 1 : 0), \
	(byte & 0x08 ? 1 : 0), \
	(byte & 0x04 ? 1 : 0), \
	(byte & 0x02 ? 1 : 0), \
	(byte & 0x01 ? 1 : 0)
	int main()
	{
	printf("Leading text "BYTETOBINARYPATTERN, BYTETOBINARY(32));
	return 0;
	}

view raw printbinary.cpp hosted with ❤ by GitHub