How do I check if an integer is even or odd using bitwise operators

Question

How do I check if an integer is even or odd using bitwise operators

Answer 1

Also in Java you will have to use if((number&1)==1){//then odd}, because in Java and C# like languages the int is not casted to boolean. You'll have to use the relational operators to return a boolean value i.e true and false unlike C and C++ like languages which treats non-zero value as true.

Answer 2

if(x & 1)                               // '&' is a bit-wise AND operator
    printf("%d is ODD\n", x);
else
    printf("%d is EVEN\n", x);

Examples:

    For 9:

      9 ->        1 0 0 1
      1 ->     &  0 0 0 1
      -------------------
      result->    0 0 0 1

So 9 AND 1 gives us 1, as the right most bit of every odd number is 1.

     For 14:

       14 ->      1 1 1 0
       1  ->   &  0 0 0 1
       ------------------
       result->   0 0 0 0

So 14 AND 1 gives us 0, as the right most bit of every even number is 0.

Answer 3

if (number & 1)
    number is odd
else // (number & 1) == 0
    number is even

For example, let's take integer 25, which is odd. In binary 25 is 00011001. Notice that the least significant bit b0 is 1.

00011001    
00000001   (00000001 is 1 in binary)
       &
--------
00000001

Answer 4

In Java,

if((num & 1)==0){
//its an even num
}
//otherwise its an odd num

Answer 5

You can do it simply using bitwise AND & operator.

if(num & 1)
{
    //I am odd number.
}

Read more over here - Checking even odd using bitwise operator in C

Answer 6

#include <iostream>
#include <algorithm>
#include <vector>

void BitConvert(int num, std::vector<int> &array){
    while (num > 0){
        array.push_back(num % 2);
        num = num / 2;
    }
}

void CheckEven(int num){
    std::vector<int> array;
    BitConvert(num, array);
    if (array[0] == 0)
        std::cout << "Number is even";
    else
        std::cout << "Number is odd";
}

int main(){
    int num;
    std::cout << "Enter a number:";
    std::cin >> num;

    CheckEven(num);
    std::cout << std::endl;

    return 0;
}