Program Check even or odd without using modulus and division operators

• Checking the number even or odd program is very easy. Anybody can solve this but there is a condition we need to see.
• When we get this question in interview "write a program to check given number is even or odd" always continues with "without using modulus and division operators".
• Before going to actual program lets see how to check a number is even or odd by using modulus and division operators.

 

 

Program to check number is even or odd by using modulus "%" operator

1. package instanceofjava;
2. import java.util.Scanner;
3.  
4. public class EvenorOdd {
5.  
6. public static void main(String []args )    {
7.  
8.     int number;
9.     Scanner in= new Scanner(System.in);
10.  
11.     System.out.println("Enter a number to check even or odd");
12.     number=in.nextInt();
13.  
14.     if((number % 2)==0){
15.         System.out.println(+number+" is Even number");
16.     }else{
17.         System.out.println(+number+" is Odd Number");
18.     }
19.  
20. }
21. }

Output:

1. Enter a number to check even or odd
2. 37
3. 37 is Odd Number

Program to check number is even or odd by using division "/" operator

1. package instanceofjava;
2. import java.util.Scanner;
3.  
4. public class EvenorOdd {
5.  
6. public static void main(String []args )    {
7.  
8.     int number;
9.     Scanner in= new Scanner(System.in);
10.  
11.     System.out.println("Enter a number to check even or odd");
12.     number=in.nextInt();
13.  
14.     if((number / 2)*2==number){
15.         System.out.println(+number+" is Even number");
16.     }else{
17.         System.out.println(+number+" is Odd Number");
18.     }
19.  
20. }
21. }

Output:

1. Enter a number to check even or odd
2. 46
3. 46 is Even Number

Without using modulus and division operators:

• The above two programs will check number is even or odd and displays result. 
• Now we need to write a program to check even or odd without using modulus and division operators.
• It is very simple if you know about operators including "BIT WISE".
• Yes using Bit Wise AND "&" operator we can check a number is even or odd.
• Before starting our program lets see how this bit wise AND "&" operator will work.

Bitwise Operators :

• Bit wise operators will work on bits at a time.
• AND : 1 & 1=1
• OR :     0 | 1= 1 , 1 | 0=1 , 1| 1= 1
• XOR:   0 ^ 1= 1 , 1^ 0=1
• NOT : !0=1

• Take two number 2 and 3
• 010 : 2
  011 : 3
  ------
  010 : 2
• ------
• Take two numbers 2 and 1
  
• 010  :2
  001  :1
  -----
  000  :0
  -----

• From above example we can say that on every even number & 1 gives 0.
• So this is our logic to be implemented in our program  if "Number & 1==0" then its even number.

Program to check number is even or odd by using  "&" operator

1. package instanceofjava;
2. import java.util.Scanner;
3.  
4. public class EvenorOdd {
5.  
6. public static void main(String []args )    {
7.  
8.     int number;
9.     Scanner in= new Scanner(System.in);
10.  
11.     System.out.println("Enter a number to check even or odd");
12.     number=in.nextInt();
13.  
14.     if((number & 1)==0){
15.         System.out.println(+number+" is Even number");
16.     }else{
17.         System.out.println(+number+" is Odd Number");
18.     }
19.  
20. }
21. }

Output:

1. Enter a number to check even or odd
2. 9
3. 9 is Odd Number

Using Shift Operators:

• We can check even or odd by using shift operators also may be it is not a better solution but  trying to cover alternative.
• Lets see how shift operators will work
• Lets do this 2 >> 1
• 2 means 010 so now we need to shift right side by 1 place
• 010
  -----
  001
• Here we added one "0" to the left side to shift right 
• So the value became 1
• Now will try left shift  001 >> 1
  001
  ----
  010
• 010<<1=001(1) and 001 >> 001=010(2)
• By this we can say if a (number >>1)<<1 gives same then that is even number. result=input
• Lets check for odd number 3
• 011>>1=001 which is 1 and 001<<1=010 which is 2 so (3>>1)>>1=2 so result!=input

Program to check number is even or odd by using Shift operator

1. package instanceofjava;
2. import java.util.Scanner;
3.  
4. public class EvenorOdd {
5.  
6. public static void main(String []args )    {
7.  
8.     int number;
9.     Scanner in= new Scanner(System.in);
10.  
11.     System.out.println("Enter a number to check even or odd");
12.     number=in.nextInt();
13.  
14.     if( ( number >> 1) <<1==number){
15.         System.out.println(+number+" is Even number");
16.     }else{
17.         System.out.println(+number+" is Odd Number");
18.     }
19.  
20. }
21. }

Output:

1. Enter a number to check even or odd
2. 64
3. 64 is Even Number

Here is the another solution for this.

1. package instanceofjava;
2. import java.util.Scanner;
3.  
4. class EvenOrOddDemo
5. {
6.  
7. public static void main(String[] args)
8. {
9.  
10. Scanner sc=new Scanner(System.in);
11.  
12. System.out.println("Enter a number to check whether it is even or odd without using Modulus
13. and Division: ");
14.  
15. int n=Integer.parseInt(sc.next());
16. float f=(float)n/(float)2;
17. int d=(int)f*2;
18.  
19. if(d==n)
20. System.out.println(n+" is a even number");
21. else
22. System.out.println(n+" is a odd number");
23. }
24. 
    
25. }

Output:

1. Enter a number to check whether it is even or odd without using Modulus and Division
2. 4
3. 4 is Even Number

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