Bit Manipulation

i) a<<b (a left shift b):- a * 2^b;

ii) a>>b(a right shift b):- a/2^b;

1. Write a program to check number is even or odd using bit manipulation.

    public class Main
    {
        public static void oddEven(int n){
            int bitMask=1;
            if((n&bitMask)==0){
                System.out.println("even");
            }else{
                System.out.println("odd");
             }
        }
        public static void main(String[] args) {
            oddEven(2);
            oddEven(3);
            oddEven(5);
        }
    }
   

   

2. Write a program to get the ith bit in a number.

    public class Main
    {
        public static int getithBit(int n, int i)
        {
            int bitMask=1<<i;
            if((n&bitMask)==0){
                return 0;
            }else{
                return 1;   
            }
        }
        public static void main(String[] args) {
            System.out.println(getithBit(15,2));//1
        }
    }
   

   

3. Write a program to set ith bit in a number.

    public class Main
    {
        public static int setithBit(int n, int i){
            int bitmask= 1<<i;
            return n|bitmask;
        }
        public static void main(String[] args) {
            System.out.println(setithBit(7,3)); //15
            System.out.println(setithBit(10,2)); //14
            System.out.println(setithBit(9,2)); //13
        }
    }
   

   

4. Write a program to clear the ith bit of a number.

    public class Main
    {
        public static int clear(int n, int i){
            int bitMask= (~(1<<i));
            return n&bitMask;
        }
        public static void main(String[] args) {
            System.out.println(clear(13,2));//9
            System.out.println(clear(4,1));//4
            System.out.println(clear(4,2));//0
        }
    }
   

5. Write a program to update the ith bit of a number with 1 or 0.

    public class Main
    {
        public static int update(int n, int i, int newBit){
            int bitMask=newBit<<i;
            return n|bitMask;
        }
        public static void main(String[] args) {
            System.out.println(update(4,2,0));//4
            System.out.println(update(4,2,1));//4
            System.out.println(update(4,1,1));//6
        }
    }
   

6. Write a program to clear the last ith bit of a number

    public class Main
    {
        public static int lastBitClear(int n, int i){
            int bitMask= ((-1)<<i);
            return n & bitMask;
        }
        public static void main(String[] args) {
            System.out.println(lastBitClear(7,2));//4
            System.out.println(lastBitClear(12,2));//12
        }
    }
   

7. Write a program to clear the range of bits in a number.

    public class Main
    {
        public static int update(int n, int i, int j){
            int a=((-1)<<(j+1));
            int b= (1<<i)-1;
            return  n & (a | b);
        }
        public static void main(String[] args) {
            System.out.println(update(10,1,3));//0
            System.out.println(update(7,2,3));//3
        }
    }
   

8. Write a program to check if a number is power of two or not.

    public class Main
    {
        public static boolean isPowerOfTwo(int n){
            return ((n&(n-1))==0);
        }
        public static void main(String[] args) {
            System.out.println(isPowerOfTwo(2));
            System.out.println(isPowerOfTwo(16));
            System.out.println(isPowerOfTwo(5));
        }
    }
   

9. Write a program to count the set bits in a number.

    public class Main
    {
        public static int count(int n){
            int count=0;
            while(n>0){
                if((n&1)!=0){
                    count++;
                }
                n=n>>1;
            }
            return count;
        }
        public static void main(String[] args) {
            System.out.println(count(15));//4
            System.out.println(count(7));//3
        }
    }
   

   

10. Write a program to perform exponentiation using bit manipulation.

    public class Main
    {
        public static int exponentiation(int a, int n){
            int ans=1;
            while(n>0){
                if((n&1)!=0){
                    ans=ans*a;
                }
                a=a*a;
                n=n>>1;
            }
            return ans;
        }
        public static void main(String[] args) {
            System.out.println(exponentiation(5,3));//125
            System.out.println(exponentiation(2,4));//16
        }
    }