# Check whether a given number is even or odd

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- Difficulty Level : Basic
- Last Updated : 05 Jul, 2022

Given a number, check whether it is even or odd.

**Examples :**

Input: 2Output: evenInput: 5Output: odd

Recommended Practice

One **simple solution** is to find the remainder after dividing by 2.

## 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` `(n % 2 == 0); }` `// Driver code` `int` `main()` `{` ` ` `int` `n = 101;` ` ` `isEven(n) ? cout << ` `"Even"` `: cout << ` `"Odd"` `;` ` ` `return` `0;` `}` |

## Java

`// Java program to` `// check for even or odd` `class` `GFG` `{` ` ` `// Returns true if n is even, else odd` ` ` `public` `static` `boolean` `isEven(` `int` `n)` ` ` `{` ` ` `return` `(n % ` `2` `== ` `0` `);` ` ` `}` ` ` ` ` `// Driver code` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` `int` `n = ` `101` `;` ` ` `if` `(isEven(n) == ` `true` `)` ` ` `System.out.print(` `"Even"` `);` ` ` `else` ` ` `System.out.print(` `"Odd"` `);` ` ` `}` `}` `// This code is contributed by rishabh_jain` |

## Python3

`# A simple Python3 code` `# to check for even or odd` `# Returns true if n is even, else odd` `def` `isEven(n):` ` ` `return` `(n ` `%` `2` `=` `=` `0` `)` ` ` `# Driver code` `n ` `=` `101` `print` `(` `"Even"` `if` `isEven(n) ` `else` `"Odd"` `)` `# This code is contributed by "Sharad_Bhardwaj".` |

## C#

`// C# program to` `// check for even or odd` `using` `System;` `class` `GFG` `{` ` ` `// Returns true if n is even, else odd` ` ` `public` `static` `bool` `isEven(` `int` `n)` ` ` `{` ` ` `return` `(n % 2 == 0);` ` ` `}` ` ` ` ` `// Driver code` ` ` `public` `static` `void` `Main()` ` ` `{` ` ` `int` `n = 101;` ` ` `if` `(isEven(n) == ` `true` `)` ` ` `Console.WriteLine(` `"Even"` `);` ` ` `else` ` ` `Console.WriteLine(` `"Odd"` `);` ` ` `}` `}` `// This code is contributed by vt_m` |

## PHP

`<?php` `// A simple PHP program to` `// check for even or odd` `// Returns true if n is` `// even, else odd` `function` `isEven(` `$n` `)` `{` ` ` `return` `(` `$n` `% 2 == 0);` `}` `// Driver code` `$n` `= 101;` `if` `(isEven != true)` ` ` `echo` `"Even"` `;` ` ` `else` ` ` `echo` `"Odd"` `;` `// This code is contributed by Ajit` `?>` |

## Javascript

`<script>` `// A simple Javascript program to` `// check for even or odd` `// Returns true if n is` `// even, else odd` `function` `isEven(n) { ` `return` `(n % 2 == 0); }` `// Driver code` ` ` `let n = 101;` ` ` `isEven(n) ? document.write(` `"Even"` `) :document.write(` `"Odd"` `);` `// This code is contributed by Mayank Tyagi` `</script>` |

**Output**

Odd

**Time Complexity: O(1)****Auxiliary Space: O(1)**

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 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;` `}` |

## C

`#include <stdio.h>` `#include <math.h>` `int` `main(){` ` ` `int` `n = 101;` ` ` `if` `(n%2==0){` ` ` `printf` `(` `"Even"` `);` ` ` `}` ` ` `else` `{` ` ` `printf` `(` `"Odd"` `);` ` ` `}` ` ` `return` `0;` `}` |

## Java

`// Java program to` `// check for even or odd` `class` `GFG` `{` ` ` `// Returns true if n` ` ` `// is even, else odd` ` ` `public` `static` `boolean` `isEven(` `int` `n)` ` ` `{` ` ` `if` `((n & ` `1` `) == ` `0` `)` ` ` `return` `true` `;` ` ` `else` ` ` `return` `false` `;` ` ` `}` ` ` ` ` `// Driver code` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` `int` `n = ` `101` `;` ` ` `if` `(isEven(n) == ` `true` `)` ` ` `System.out.print(` `"Even"` `);` ` ` `else` ` ` `System.out.print(` `"Odd"` `);` ` ` `}` `}` `// This code is contributed by rishabh_jain` |

## Python3

`# A Python3 code program` `# to check for even or odd` `# Returns true if n is even, else odd` `def` `isEven(n):` ` ` ` ` `# n&1 is 1, then odd, else even` ` ` `return` `(` `not` `(n & ` `1` `))` ` ` `# Driver code` `n ` `=` `101` `;` `print` `(` `"Even"` `if` `isEven(n) ` `else` `"Odd"` `)` `# This code is contributed by "Sharad_Bhardwaj".` |

## C#

`// C# program to` `// check for even or odd` `using` `System;` `class` `GFG` `{` ` ` `// Returns true if n` ` ` `// is even, else odd` ` ` `public` `static` `bool` `isEven(` `int` `n)` ` ` `{` ` ` `if` `((n & 1) == 0)` ` ` `return` `true` `;` ` ` `else` ` ` `return` `false` `;` ` ` `}` ` ` ` ` `// Driver code` ` ` `public` `static` `void` `Main()` ` ` `{` ` ` `int` `n = 101;` ` ` `if` `(isEven(n) == ` `true` `)` ` ` `Console.WriteLine(` `"Even"` `);` ` ` `else` ` ` `Console.WriteLine(` `"Odd"` `);` ` ` `}` `}` `// This code is contributed by vt_m.` |

## PHP

`<?php` `// A simple PHP program to` `// check for even or odd` ` ` `// Returns true if n is` `// even, else odd` `function` `isEven(` `$n` `)` `{` ` ` `return` `(!(` `$n` `& 1));` `}` ` ` `// Driver code` `$n` `= 101;` `if` `(isEven(` `$n` `) == true)` ` ` `echo` `"Even"` `;` `else` ` ` `echo` `"Odd"` `;` ` ` `// This code is contributed by Smitha` `?>` |

## Javascript

`<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));` `}` `// Driver code` `let n = 101;` `isEven(n)? document.write(` `"Even"` `) :` ` ` `document.write(` `"Odd"` `);` `// This code is contributed by Manoj.` `</script>` |

**Output**

Odd

**Time Complexity: O(1)****Auxiliary Space: O(1)**

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My Personal Notes

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