Even or Odd using division operator
Checking Even or Odd Number in Java without remainder or modulus operator
Division operator in Java returns quotient, if we first divide a number by two and then multiply result which is quotient to two, we will get a number which is always less in case of odd number and always equal in case of even number. By using this property you can check if a number is odd or even :
int quotient = number/2;
if(quotient*2== number){
System.out.println("Even number");
}
1. Odd or Even checking using bitwise AND operator
Another way to solve this problem without using modulus operator is, by using bitwise AND operator. Since integer numbers are represented as 2's complement and even number has 0 as there LSB, if we perform a bitwise AND between 1 and number, result will be zero. This would be enough to check if a number is even or odd in Java.
if((number & 1) == 0){
System.out.println("Even number");
}
Here is a complete Java program to test if number is even or odd without using modulus operators. This program uses both the approach e.g. using division and bitwise operator to identify if a number is odd or even.
/**
* Java program to check if a number is even or odd without using modulus or remainder
* operator. This examples uses bitwise AND and division operator to check evenness.
*
* @author Javin Paul
*/
public class EvenOrOdd {
public static void main(String args[]) {
//Testing, let's test both methods for positive and negative integers
System.out.println("Checking if a number is even or odd using
division and bitwise operator");
for(int i= -1; i<2; i++){
isEvenOrOdd(i); //calling division operator method
isOddOrEven(i); //calling
}
}
/*
* checking even and odd number without using modulus or remainder operator, Instead
* this method uses division operator.
*/
public static void isEvenOrOdd(int number){
int quotient = number/2;
if(quotient*2== number){
System.out.println("Using division operator: " + number + " is Even number");
}else{
System.out.println("Using division operator: " + number + " is Odd number");
}
}
/*
* This method uses bitwise AND (&) operator to check if a number is
* even or odd in Java
*/
public static void isOddOrEven(int number){
if((number & 1) == 0){
System.out.println("Using bitwise operator: " + number + " is Even number");
}else{
System.out.println("Using bitwise operator: " + number + " is Odd number");
}
}
}
Output:
Checking if a number is even or odd using division and bitwise operator
Using division operator: -1 is Odd number
Using bitwise operator: -1 is Odd number
Using division operator: 0 is Even number
Using bitwise operator: 0 is Even number
Using division operator: 1 is Odd number
Using bitwise operator: 1 is Odd number
That's all on How to find if an integer is even or odd in Java, without using modulus or remainder operator. The interviewer may twist this question more, by not allowing you to either use a bitwise operator or division operator, that's why it's better to know different alternatives to solve a problem, even if you think that a trivial programming exercise.