CareerCup

int SwapBit(int n, int i, int j) {
	int bit_i = (n & (1 << i)) >> i;	// get bit i
	int bit_j = (n & (1 << j)) >> j;	// get bit j
	int mask = ~((1 << i) | (1 << j));	// mask to unset bits i and j
	return (n & mask) | (bit_i << j) | (bit_j << i);
}

public class SwapIthAndJthBits 
{
	public int swap(int n, int i, int j)
	{
		int a = (1 << i);
		int b = (1 << j);
		
		int x = n & a;
		int y = n & b;
		if ( (x > 0 && y == 0)
			||(x == 0 && y > 0))
		{
		    x = (1<<i);
		    y = (1<<j);
		    n = n ^ (x | y);
		}
		return n;
	}
	/**
	 * @param args
	 */
	public static void main(String[] args) 
	{
	    int n = 29;
	    int r = new SwapIthAndJthBits().swap(n, 1, 4);
	    System.out.println(r);
	}

}

public class Interview {

	public static void main(String[] args) {
		int a = 0x800F0001;
		System.out.println(intToBinaryString(a) + "\n" + intToBinaryString(swap(a, 1, 12)));
	}

	private static int swap(int n, int i, int j) {
		int swap = 0;
		int a = 0x80000000 >>> i;
		int b = 0x80000000 >>> j;
		int x = n & a;
		int y = n & b;
		
		if (((x!=0) && (y==0)) || ((y!=0) && (x==0))) {
			swap = n ^ (a | b);
		} else {
			swap = n;
		}
		
		return swap;
	}

	private static String intToBinaryString(int n) {
		return String.format("%32s", Integer.toBinaryString(n)).replace(' ', '0');
	}

Output:

10000000000011110000000000000001
11000000000001110000000000000001

int main () {
unsigned char v = 128;
int swp1 = 7;
int swp2 = 0;
unsigned char tmp1 = (1 << swp1) & v;
unsigned char tmp2 = (1 << swp2) & v;
if (swp1 > swp2) {
tmp1 = tmp1 >> (swp1 - swp2);
tmp2 = tmp2 << (swp1 - swp2);
} else {
tmp1 = tmp1 << (swp2 - swp1);
tmp2 = tmp2 >> (swp2 - swp1);
}
tmp1 = tmp1 | tmp2 ;
v &= ~(1 << swp1);
v &= ~(1 << swp2);

printf("Final value = %d\n", tmp1 | v);
}

int Swap ( int n, int i, int j )
{
    int a = ((1<<i) | (1<<j)) ;
    int b = (n ^ a) & a ;
    if ( (b!=0) && (b!=a) )
        return ((n & ~a) | b) ;
    else
        return n ;
}

#include <stdio.h>

int main()
{
int str;
int m = 0, n = 0;
int i,j;
printf("enter integer, i value, j value \n");
scanf("%d%d%d",&str,&i,&j);
if(str & (1 << i))
m = 1;
if(str & (1 << j))
n = 1;
if(m)
{
str |= (1 << j);
}
else
{
str &= (~(1<<j));
}

if(n)
{
str |= (1 << i);
}
else
{
str &= (~(1<<i));
}

printf("str = %d\n", str);
return 0;
}

if(word[i] != word[i]) {
word[i] = word[i] == 0 ? 1 : 0;
word[j] = word[j] == 0 ? 1 : 0;
}

//Careercup
//How do you swap bits at indexes i & j of a 32-bit memory word?
#include<iostream>

using namespace std;

int main()
{
   int num = 0;
   int i = 0;
   int j = 0;

   cout<<"Enter Num \n";
   cin>>num;
  
   do
   {
      cout<<"\n Enter i position (0-31)"<<endl;
      cin>>i;
   }while(i < 0 || i > 31);

   do
   {
      cout<<"\n Enter j position (0-31)"<<endl;
      cin>>j;
   }while(j < 0 || j > 31);

   num = num ^ (1<<i) ^ (1 <<j);

   cout<<"After Swaping bits num = "<<num;
}