Check a number is odd or even without modulus operator
Last Updated :
31 May, 2022
Given a number, check whether it is even or odd.
Examples :
Input: n = 11
Output: Odd
Input: n = 10
Output: Even
Method 1: Using Loop.
The idea is to start with a boolean flag variable as true and switch it n times. If flag variable gets original value (which is true) back, then n is even. Else n is false.
Below is the implementation of this idea.
C++
// A simple C++ program to check for
// even or odd
#include <iostream>
using namespace std;
// Returns true if n is even, else odd
bool isEven(int n)
{
bool isEven = true;
for (int i=1; i <= n; i++)
isEven = !isEven;
return isEven;
}
// Driver code
int main()
{
int n = 101;
isEven(n) ? cout << "Even" : cout << "Odd";
return 0;
}
// A simple Java program to
// check for even or odd
class GFG {
// Returns true if n
// is even, else odd
static boolean isEven(int n)
{
boolean isEven = true;
for (int i = 1; i <= n; i++)
isEven = !isEven;
return isEven;
}
// Driver Code
public static void main(String args[])
{
int n = 101;
if(isEven(n))
System.out.println("Even");
else
System.out.println("Odd");
}
}
// This code is contributed by Sam007
# A simple Python program to
# check for even or odd
# Returns true if n is even,
# else odd
def isEven(n):
isEven = True;
for i in range(1, n+1):
if isEven == True:
isEven = False;
else:
isEven = True;
return isEven;
# Driver code
n = 101;
if isEven(n) == True:
print ("Even");
else:
print ("Odd");
# This code is contributed by
# Manish Shaw (manishshaw1)
// A simple C# program to check for
// even or odd
using System;
public class GFG {
// Returns true if n is even,
// else odd
static bool isEven(int n)
{
bool isEven = true;
for (int i = 1; i <= n; i++)
isEven = !isEven;
return isEven;
}
// Driver code
public static void Main()
{
int n = 101;
if(isEven(n))
Console.Write("Even");
else
Console.Write("Odd");
}
}
// This code is contributed by Sam007.
<?php
// A simple PHP program to check for
// even or odd
// Returns true if n is even,
// else odd
function isEven($n)
{
$isEven = true;
for ($i = 1; $i <= $n; $i++)
$isEven = !$isEven;
return $isEven;
}
// Driver code
$n = 101;
$is=isEven($n) ? "Even" : "Odd";
echo "$is"
// This code is contributed by ajit
?>
<script>
// A simple Javascript program to check
// for even or odd
// Returns true if n is even,
// else odd
function isEven(n)
{
let isEven = true;
for(let i = 1; i <= n; i++)
isEven = !isEven;
return isEven;
}
// Driver code
let n = 101;
if (isEven(n))
document.write("Even");
else
document.write("Odd");
// This code is contributed by mukesh07
</script>
Time Complexity : O(n)
Auxiliary Space: O(1)
Method 2: By multiply and divide by 2. Divide the number by 2 and multiply by 2 if the result is same as input then it is an even number else it is an odd number.
C++
// A simple C++ program to check for
// even or odd
#include <iostream>
using namespace std;
// Returns true if n is even, else odd
bool isEven(int n)
{
// Return true if n/2 does not result
// in a float value.
return ((n / 2) * 2 == n);
}
// Driver code
int main()
{
int n = 101;
isEven(n) ? cout << "Even" : cout << "Odd";
return 0;
}
// A simple Java program
// to check for even or odd
class GFG {
// Returns true if n
// is even, else odd
static boolean isEven(int n)
{
// Return true if
// n/2 does not result
// in a float value.
return ((n / 2) * 2 == n);
}
// Driver code
public static void main(String[] args)
{
int n = 101;
if(isEven(n) != false)
System.out.print( "Even" );
else
System.out.print( "Odd" );
}
}
// This code is contributed by
// Smitha Dinesh Semwal.
# A simple Python 3 program
# to check for even or odd
# Returns true if n
# is even, else odd
def isEven(n):
# Return true if
# n/2 does not result
# in a float value.
return (int(n / 2) * 2 == n)
# Driver code
n = 101
if(isEven(n) != False):
print("Even")
else:
print("Odd")
# This code is contributed by
# Smitha Dinesh Semwal.
// A simple C# program
// to check for even or odd
using System;
class GFG {
// Returns true if n
// is even, else odd
static bool isEven(int n)
{
// Return true if
// n/2 does not result
// in a float value.
return ((n / 2) * 2 == n);
}
// Driver code
public static void Main(String[] args)
{
int n = 101;
if(isEven(n) != false)
Console.Write("Even");
else
Console.Write("Odd");
}
}
// This code is contributed by
// Smitha Dinesh Semwal.
<?php
// A simple PHP program to
// check for even or odd
// Returns true if n
// is even, else odd
function isEven($n)
{
// Return true if n/2
// does not result
// in a float value.
return ((int)($n / 2) * 2 == $n);
}
// Driver code
$n = 101;
if(isEven($n))
echo ("Even");
else
echo ("Odd");
// This code is contributed by
// Manish Shaw (manishshaw1)
?>
<script>
// A simple Javascript program to
// check for even or odd
// Returns true if n is even,
// else odd
function isEven(n)
{
// Return true if n/2 does not result
// in a float value.
return (parseInt(n / 2, 10) * 2 == n);
}
// Driver code
let n = 101;
isEven(n) ? document.write("Even") :
document.write("Odd");
// This code is contributed by divyeshrabadiya07
</script>
Time Complexity : O(1)
Auxiliary Space: O(1)
Method 3: Using Bitwise operator &.
A better solution is to use bitwise operators. We need to check whether last bit is 1 or not. If last bit is 1 then the number is odd, otherwise always even.
Explanation:
input : 5 // odd
00000101
& 00000001
--------------
00000001
--------------
input : 8 //even
00001000
& 00000001
--------------
00000000
--------------
Below is the implementation of the idea.
C++
// A simple C++ program to check for
// even or odd
#include <iostream>
using namespace std;
// Returns true if n is even, else odd
bool isEven(int n)
{
// n&1 is 1, then odd, else even
return (!(n & 1));
}
// Driver code
int main()
{
int n = 101;
isEven(n) ? cout << "Even" : cout << "Odd";
return 0;
}
// A simple Java program to check for
// even or odd
import java.io.*;
import java.util.*;
public class GFG {
// Returns 0 if n
// is even, else odd
static int isEven(int n)
{
// n&1 is 1, then
// odd, else even
return (n & 1);
}
// Driver code
public static void main(String args[])
{
int n = 101;
if(isEven(n)==0)
System.out.print("Even");
else
System.out.print("Odd");
}
}
// This code is contributed
// by Manish Shaw (manishshaw1)
# A simple Python program to
# check for even or odd
# Returns 0 if n
# is even, else odd
def isEven(n) :
# n&1 is 1, then
# odd, else even
return (n & 1);
# Driver code
n = 101;
if(isEven(n) == 0) :
print ("Even");
else :
print ("Odd");
# This code is contributed
# by Manish Shaw (manishshaw1)
// A simple C# program to check for
// even or odd
using System;
using System.Collections.Generic;
class GFG {
// Returns 0 if n
// is even, else odd
static int isEven(int n)
{
// n&1 is 1, then
// odd, else even
return (n & 1);
}
// Driver code
public static void Main()
{
int n = 101;
if(isEven(n)==0)
Console.Write("Even");
else
Console.Write("Odd");
}
}
// This code is contributed
// by Manish Shaw (manishshaw1)
<?php
// A simple PHP program to
// check for even or odd
// Returns 0 if n
// is even, else odd
function isEven($n)
{
// n&1 is 1, then
// odd, else even
return ($n & 1);
}
// Driver code
$n = 101;
if(isEven($n) == 0)
echo ("Even");
else
echo ("Odd");
// This code is contributed
// by Manish Shaw (manishshaw1)
?>
<script>
// A simple Javascript program to check for even or odd
// Returns true if n is even, else odd
function isEven(n)
{
// n&1 is 1, then odd, else even
return (!(n & 1));
}
let n = 101;
isEven(n) ? document.write("Even") : document.write("Odd");
</script>
Time Complexity : O(1)
Auxiliary Space: O(1)
Similar Reads
Check if a Number is Odd or Even using Bitwise Operators Given a number n, the task is to check whether the number is even or odd using Bitwise Operators.Examples: Input: n = 11 Output: OddInput: n = 10 Output: Even Following Bitwise Operators can be used to check if a number is odd or even:1. Using Bitwise XOR operator: The idea is to check whether the l
6 min read
Check if a Number is Odd or Even using Bitwise Operators Given a number n, the task is to check whether the number is even or odd using Bitwise Operators.Examples: Input: n = 11 Output: OddInput: n = 10 Output: Even Following Bitwise Operators can be used to check if a number is odd or even:1. Using Bitwise XOR operator: The idea is to check whether the l
6 min read
Check whether a given number is even or odd Given a number n, check whether it is even or odd. Return true for even and false for odd.Examples: Input: n = 15Output: falseExplanation: 15 % 2 = 1, so 15 is odd .Input: n = 44Output: trueExplanation: 44 % 2 = 0, so 44 is even.Table of Content[Naive Approach] By Finding the Remainder - O(1) Time a
4 min read
Check whether a given number is even or odd Given a number n, check whether it is even or odd. Return true for even and false for odd.Examples: Input: n = 15Output: falseExplanation: 15 % 2 = 1, so 15 is odd .Input: n = 44Output: trueExplanation: 44 % 2 = 0, so 44 is even.Table of Content[Naive Approach] By Finding the Remainder - O(1) Time a
4 min read
Check whether bitwise OR of N numbers is Even or Odd Given an array arr[] containing N numbers. The task is to check whether the bitwise-OR of the given N numbers is even or odd. Examples: Input : arr[] = { 2, 12, 20, 36, 38 }Output : Even Bit-wise OR Input : arr[] = { 3, 9, 12, 13, 15 }Output : Odd Bit-wise OR A Simple Solution is to first find the O
8 min read
Check whether bitwise AND of N numbers is Even or Odd Given an array arr[] containing N numbers. The task is to check whether the bitwise-AND of the given N numbers is even or odd.Examples: Input: arr[] = { 2, 12, 20, 36, 38 } Output: Even Input: arr[] = { 3, 9, 17, 13, 15 } Output: Odd A Simple Solution is to first find the AND of the given N numbers,
7 min read