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.
// 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> |
Odd
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.
// 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> |
Odd
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.
// 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> |
Odd
Time Complexity : O(1)
Auxiliary Space: O(1)