Sum of all odd natural numbers in range L and R

11 Jul, 2022
Given two integers L and R, the task is to find the sum of all odd natural numbers in range L and R inclusive. Examples: 
Input: L = 2, R = 5
Output: 8
3 + 5 = 8

Input: L = 7, R = 13
Output: 40
A naive approach is to traverse from L to R and summate the elements to get the answer. An efficient approach is to use the formula for calculating the sum of all odd natural numbers upto R and L-1 and then subtract sum(R)-sum(L-1).Below is the implementation of the above approach:  
C++
Java
Python3
C#
PHP
Javascript
// C++ program to print the sum// of all numbers in range L and R#include <bits/stdc++.h>using namespace std; // Function to return the sum of// all odd natural numbersint sumOdd(int n){    int terms = (n + 1) / 2;    int sum = terms * terms;    return sum;} // Function to return the sum// of all odd numbers in range L and Rint suminRange(int l, int r){    return sumOdd(r) - sumOdd(l - 1);} // Driver Codeint main(){    int l = 2, r = 5;    cout << "Sum of odd natural numbers from L to R is "         << suminRange(l, r);     return 0;}
// Java program to print the sum// of all numbers in range L and R import java.io.*; class GFG {      // Function to return the sum of// all odd natural numbersstatic int sumOdd(int n){    int terms = (n + 1) / 2;    int sum = terms * terms;    return sum;} // Function to return the sum// of all odd numbers in range L and Rstatic int suminRange(int l, int r){    return sumOdd(r) - sumOdd(l - 1);} // Driver Codepublic static void main (String[] args) {            int l = 2, r = 5;    System.out.print( "Sum of odd natural numbers from L to R is "        + suminRange(l, r));    }}// This code is contributed by shs..
# Python 3 program to print the sum# of all numbers in range L and R # Function to return the sum of# all odd natural numbersdef sumOdd(n):    terms = (n + 1)//2    sum1 = terms * terms    return sum1 # Function to return the sum# of all odd numbers in range L and Rdef suminRange(l, r):    return sumOdd(r) - sumOdd(l - 1)     # Driver codel = 2; r = 5print("Sum of odd natural number",      "from L to R is", suminRange(l, r)) # This code is contributed by Shrikant13
// C# program to print the sum// of all numbers in range L and Rusing System; class GFG{     // Function to return the sum of// all odd natural numbersstatic int sumOdd(int n){    int terms = (n + 1) / 2;    int sum = terms * terms;    return sum;} // Function to return the sum// of all odd numbers in range L and Rstatic int suminRange(int l, int r){    return sumOdd(r) - sumOdd(l - 1);} // Driver Codepublic static void Main (){    int l = 2, r = 5;    Console.WriteLine( "Sum of odd natural numbers " +                "from L to R is " + suminRange(l, r));}} // This code is contributed by shs..
<?php//PHP program to print the sum// of all numbers in range L and R// Function to return the sum of// all odd natural numbersfunction sumOdd($n){    $terms = (int)($n + 1) / 2;    $sum = $terms * $terms;    return $sum;} // Function to return the sum// of all odd numbers in range L and Rfunction  suminRange($l, $r){    return sumOdd($r) - sumOdd($l - 1);} // Driver Code     $l = 2;    $r = 5;    echo "Sum of odd natural numbers from L to R is ",         suminRange($l, $r); ?>
<script> //JavaScript program to print the sum// of all numbers in range L and R // Function to return the sum of// all odd natural numbersfunction sumOdd(n){    terms = (n + 1) / 2;    sum = terms * terms;    return sum;} // Function to return the sum// of all odd numbers in range L and Rfunction suminRange(l, r){    return sumOdd(r) - sumOdd(l - 1);} // Driver Code let    l = 2;let    r = 5;    document.write("Sum of odd natural numbers from L to R is "+        suminRange(l, r));         // This code is contributed by sravan kumar </script>
Sum of odd natural numbers from L to R is 8
 
Time Complexity: O(1)
Auxiliary Space: O(1)
Shashank12
Sach_Code
shrikanth13
sravankumar8128
subhammahato348
series
series-sum
Mathematical
Mathematical
series
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.