# Count Odd and Even numbers in a range from L to R

Given two numbers L and R, the task is to count the number of odd numbers in the range L to R.**Examples:**

Input:l = 3, r = 7Output:3 2

Count of odd numbers is 3 i.e. 3, 5, 7

Count of even numbers is 2 i.e. 4, 6Input:l = 4, r = 8Output:2

**Approach:** Total numbers in the range will be **(R – L + 1)** i.e. N.

- If N is even then the count of both odd and even numbers will be
**N/2**. - If N is odd,
- If L or R is odd, then the count of odd number will be
**N/2 + 1**and even numbers =**N – countofOdd**. - Else, count of odd numbers will be
**N/2**and even numbers =**N – countofOdd**.

- If L or R is odd, then the count of odd number will be

Below is the implementation of the above approach:

## C++

`// C++ implementation of the above approach` `#include <bits/stdc++.h>` `using` `namespace` `std;` `// Return the number of odd numbers` `// in the range [L, R]` `int` `countOdd(` `int` `L, ` `int` `R){` ` ` `int` `N = (R - L) / 2;` ` ` `// if either R or L is odd` ` ` `if` `(R % 2 != 0 || L % 2 != 0)` ` ` `N += 1;` ` ` `return` `N;` `}` `// Driver code` `int` `main()` `{` ` ` `int` `L = 3, R = 7;` ` ` `int` `odds = countOdd(L, R);` ` ` `int` `evens = (R - L + 1) - odds;` ` ` ` ` `cout << ` `"Count of odd numbers is "` `<< odds << endl;` ` ` `cout << ` `"Count of even numbers is "` `<< evens << endl;` ` ` `return` `0;` `}` `// This code is contributed by Rituraj Jain` |

## Java

`// Java implementation of the above approach` `class` `GFG {` ` ` `// Return the number of odd numbers` ` ` `// in the range [L, R]` ` ` `static` `int` `countOdd(` `int` `L, ` `int` `R)` ` ` `{` ` ` `int` `N = (R - L) / ` `2` `;` ` ` `// if either R or L is odd` ` ` `if` `(R % ` `2` `!= ` `0` `|| L % ` `2` `!= ` `0` `)` ` ` `N++;` ` ` `return` `N;` ` ` `}` ` ` `// Driver code` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` `int` `L = ` `3` `, R = ` `7` `;` ` ` `int` `odds = countOdd(L, R);` ` ` `int` `evens = (R - L + ` `1` `) - odds;` ` ` `System.out.println(` `"Count of odd numbers is "` `+ odds);` ` ` `System.out.println(` `"Count of even numbers is "` `+ evens);` ` ` `}` `}` |

## Python 3

`# Python 3 implementation of the` `# above approach` `# Return the number of odd numbers` `# in the range [L, R]` `def` `countOdd(L, R):` ` ` `N ` `=` `(R ` `-` `L) ` `/` `/` `2` ` ` `# if either R or L is odd` ` ` `if` `(R ` `%` `2` `!` `=` `0` `or` `L ` `%` `2` `!` `=` `0` `):` ` ` `N ` `+` `=` `1` ` ` `return` `N` `# Driver code` `if` `__name__ ` `=` `=` `"__main__"` `:` ` ` ` ` `L ` `=` `3` ` ` `R ` `=` `7` ` ` `odds ` `=` `countOdd(L, R)` ` ` `evens ` `=` `(R ` `-` `L ` `+` `1` `) ` `-` `odds` ` ` `print` `(` `"Count of odd numbers is"` `, odds)` ` ` `print` `(` `"Count of even numbers is"` `, evens)` `# This code is contributed by ita_c` |

## C#

`// C# implementation of the above approach` `using` `System;` `class` `GFG` `{` ` ` `// Return the number of odd numbers` ` ` `// in the range [L, R]` ` ` `static` `int` `countOdd(` `int` `L, ` `int` `R)` ` ` `{` ` ` `int` `N = (R - L) / 2;` ` ` `// if either R or L is odd` ` ` `if` `(R % 2 != 0 || L % 2 != 0)` ` ` `N++;` ` ` `return` `N;` ` ` `}` ` ` `// Driver code` ` ` `public` `static` `void` `Main()` ` ` `{` ` ` `int` `L = 3, R = 7;` ` ` `int` `odds = countOdd(L, R);` ` ` `int` `evens = (R - L + 1) - odds;` ` ` `Console.WriteLine(` `"Count of odd numbers is "` `+ odds);` ` ` `Console.WriteLine(` `"Count of even numbers is "` `+ evens);` ` ` `}` `}` `// This code is contributed by Ryuga` |

## PHP

`<?php` `// PHP implementation of the above approach` `// Return the number of odd numbers` `// in the range [L, R]` `function` `countOdd(` `$L` `, ` `$R` `)` `{` ` ` `$N` `= (` `$R` `- ` `$L` `) / 2;` ` ` `// if either R or L is odd` ` ` `if` `(` `$R` `% 2 != 0 || ` `$L` `% 2 != 0)` ` ` `$N` `++;` ` ` `return` `$N` `;` `}` `// Driver code` `$L` `= 3; ` `$R` `= 7;` `$odds` `= countOdd(` `$L` `, ` `$R` `);` `$evens` `= (` `$R` `- ` `$L` `+ 1) - ` `$odds` `;` `echo` `"Count of odd numbers is "` `. ` `$odds` `. ` `"\n"` `;` `echo` `"Count of even numbers is "` `. ` `$evens` `;` `// This code is contributed` `// by Akanksha Rai` `?>` |

## Javascript

`<script>` `// Javascript implementation` `// of the above approach` `// Return the number of odd numbers` `// in the range [L, R]` `function` `countOdd( L, R){` ` ` `let N = Math.floor((R - L) / 2);` ` ` `// if either R or L is odd` ` ` `if` `(R % 2 != 0 || L % 2 != 0)` ` ` `N += 1;` ` ` `return` `N;` `}` ` ` `// Driver Code` ` ` ` ` `let L = 3, R = 7;` ` ` `let odds = countOdd(L, R);` ` ` `let evens = (R - L + 1) - odds;` ` ` ` ` `document.write(` ` ` `"Count of odd numbers is "` `+ odds + ` `"</br>"` ` ` `);` ` ` `document.write(` ` ` `"Count of even numbers is "` `+ evens + ` `"</br>"` ` ` `);` ` ` ` ` `</script>` |

**Output:**

Count of odd numbers is 3 Count of even numbers is 2