# 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 = 7

Output:3 2

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

Count of even numbers is 2 i.e. 4, 6

Input:l = 4, r = 8

Output: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 ` |

*chevron_right*

*filter_none*

## 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); ` ` ` `} ` `} ` |

*chevron_right*

*filter_none*

## 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 ` |

*chevron_right*

*filter_none*

## 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 ` |

*chevron_right*

*filter_none*

## 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 ` `?> ` |

*chevron_right*

*filter_none*

**Output:**

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

## Recommended Posts:

- Count the numbers divisible by 'M' in a given range
- Count factorial numbers in a given range
- Count of Numbers in Range where the number does not contain more than K non zero digits
- Count numbers with unit digit k in given range
- Count of common multiples of two numbers in a range
- Count all the numbers in a range with smallest factor as K
- Count numbers from range whose prime factors are only 2 and 3
- Numbers in range [L, R] such that the count of their divisors is both even and prime
- Count numbers in range L-R that are divisible by all of its non-zero digits
- Count of Numbers in a Range where digit d occurs exactly K times
- Program to find count of numbers having odd number of divisors in given range
- Count numbers in a range having GCD of powers of prime factors equal to 1
- Count of numbers between range having only non-zero digits whose sum of digits is N and number is divisible by M
- Count of Numbers in Range where first digit is equal to last digit of the number
- Numbers within a range that can be expressed as power of two numbers

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.