Odd numbers recursion java. I am unsuccessful and would appreciate .


  1. Odd numbers recursion java. Jul 12, 2025 · Given a number N, the task is to print the numbers from N to 1. I also have to handle the cases when the number is negative. Jul 23, 2025 · The problem is very similar to our old post Segregate 0s and 1s in an array. My first thought was to turn the int into a str Nov 6, 2015 · I need to write a recursive method to count the number of odd integers in an array. My assignment dictates that i accomplish this using recursion. Aug 28, 2024 · In this article, we will check How to calculate the sum of N natural numbers using an iterative approach i. Mar 5, 2021 · This might be simple but I'm new to recursion in c. I have the below snippet of code to use a recursive method to add the sum of odd numbers. I have the below snippet of code to use a recursive method to add the sum of odd numbers. The media could not be loaded, either because the server or network failed or because the format is not supported. Please refer complete article on Merge Nov 14, 2022 · I have to write a method that returns/prints the odd numbers between 1 and 100, but I have to use another method, which checks whether a given integer is odd or not: static boolean isOdd(int c) { Oct 14, 2014 · I am trying to write a method that finds how many odd numbers are between first position and last position. Jul 23, 2025 · The idea is to first separate all odd and even numbers into two different arrays. My cur Nov 29, 2024 · In this article, we will discuss the concept of Calculate power of a number using recursive function in Java language - calculate power of a number Mar 15, 2020 · I'm having trouble writing a recursive method that is meant to remove any odd digits from an int - for example: evenDigits(123456) should return 246. I think I need to I would like to write a recursive method that expects an integer N as input and then adds and returns all odd numbers from 1 to N inclusive, but how do I give the sum? Is my solution right? pub Jun 2, 2025 · Write a recursive function sum (n) that calculates the sum of all odd numbers in an array arr up to index n. My cur Oct 3, 2025 · Merge sort is a popular sorting algorithm known for its efficiency and stability. Below is the implementation of the above approach. This method Nov 1, 2014 · I have to write a power method in Java. e. Aug 5, 2025 · The base case occurs when the index reaches the end of the array, returning the accumulated sum. Divide the number by 10 with help of '/' operator to remove the rightmost digit Check the base case with n = 0 Print or return the Jul 23, 2025 · [Naive Approach] By storing all Fibonacci numbers - O (n) time and O (n) space The idea is simple we will first generate all Fibonacci numbers up to a given number n, then compute and print the sum of these Fibonacci numbers. Here's a step-by-step explanation of how merge sort works: Divide: Divide the list or array Nov 29, 2024 · In this article, we will discuss the concept of Calculate power of a number using recursive function in Java language - calculate power of a number Mar 15, 2020 · I'm having trouble writing a recursive method that is meant to remove any odd digits from an int - for example: evenDigits(123456) should return 246. Examples: Input: 12345 Output: 15 Explanation: Sum of digits → 1 + 2 + 3 + 4 + 5 = 15 Input: 45632 Output: 20 Approach: To understand the algorithm, consider the number 12345 and refer to the illustration below. java and implement a recursive method specified below: public static void permutation(int num) This m Any number when divided by 2 gives a remainder other than zero which is an odd number. Example 2 : Factorial of a Number The factorial of a number n (where n >= 0) is the product of all positive integers from 1 to n. Also, say I input 10101 int Apr 10, 2014 · I'm making a program where it takes a list of elements in an arraylist and using recursion, gets the even and odd elements. Jul 11, 2025 · In Java, Recursion is a process in which a function calls itself directly or indirectly is called recursion and the corresponding function is called a recursive function. Dec 10, 2020 · Here is the source code of the Java Program to Find the sum of Odd numbers using recursion in an array. The merge () function is used for merging two halves. It follows the Divide and Conquer approach. Jul 23, 2025 · Print even and odd numbers in a given range using recursion Last Updated : 23 Jul, 2025 May 14, 2025 · Learn how to write a recursive method in Java to find the sum of all odd numbers in an array. By following this step-by-step solution and implementing the provided Java code, you can create a recursive method to test if a number is odd without using the modulus operator. Apr 11, 2023 · In this article, we are going to write a java program to find the sum of first n Odd and Even numbers. I have already coded the iterative method successfully that adds the sum of all odd numbers between n and m Nov 27, 2024 · In this tutorial, we discuss a concept of Java program to check odd or even using recursion and how to find it Feb 3, 2017 · I tried to write a simple java program which counts how many odd digits there are inside a number (for example, for input "123" the program should return 2). Declare an integer array say ‘ A[] ’ Prompt the user to enter the elements inside the array. Do refer to the below illustration to get what is supposed to be conveyed out basics here via generic Illustration for any random integer, check whether it is even or odd. I tried using a for loop but I can only Jan 23, 2022 · Basically, I am trying to write a method where a number is inputted and if there are more odd digits than even digits in the number, it returns "true", and else, false. 4) If Dec 19, 2022 · Output: 10 4 + 6 = 10 Approach: Write a recursive function that takes the array as an argument with the sum variable to store the sum and the index of the element that is under consideration. In this step you apply your condition n % 2 != 1 and check whether the number is even or odd. So for an input of n=3, the first algorithm will compute 1+3+5, while your algorithm will compute 1+3. I want to find the sum of odd integers based on user's input. ?? Java Program With Recursive Function To Find The Sum Of Odd Numbers Upto Any Limit (Hindi) Jun 22, 2022 · All the numbers ending with 1, 3, 5,7, and 9 are odd numbers. Power function, pow (x,n) in Java implemented as native function using bit wise calculations of numbers for faster calculation. A number can be divided into two categories based on whether when it is divided by ‘2’ gives remainder ‘0’ or ‘1’. Perfect for DSA practice! Feb 4, 2014 · I'm using a method to sort out an array with even numbers coming out in the front and odd numbers in the back of the array. Here's my code so far: public static int countOdd(int[] numbers, int startIndex Dec 6, 2014 · The original computes the sum of the first n odd numbers. using a for a loop and Mathematical Formulae. . Concepts Recursion: Repeatedly check whether How to add the sum of an array with a recursion, but I don't understand how to use recursion. 3) Keep decrementing hi index until we see an even number. Here we are writing a Java program using a while loop to print all the odd numbers between 1 and 100. Oct 26, 2016 · The recursion stops here and 1 is returned as a result (because it's the smallest odd number > 0) define a recursion stepreturn (n % 2 != 1) ? oddSum (n - 1) : oddSum (n - 1) + n that is called everytime the method has not yet reached the base case. Extract the last digit: 12345 % 10 = 5, pass 1234 to the next step. Next, it will find the sum of odd numbers within this array using For Loop. Intuitions, example walk through, and complexity analysis. nextInt Learn to sum the first N odd numbers using recursion. Recursion may be a bit difficult to understand. m] and arr [m+1. Nov 27, 2024 · In this tutorial, we discuss a concept of Java program to check odd or even using recursion and how to find it Aug 28, 2025 · Problem Statement: Write a recursive function sum (n) that calculates the sum of all odd numbers in an array arr up to index n. Learn efficient algorithms—start coding smarter today! Aug 5, 2022 · Problem with recursion for odd number in sequence Java Asked 2 years, 7 months ago Modified 2 years, 7 months ago Viewed 58 times GeeksforGeeks | A computer science portal for geeks Your title is "Adding Odd Numbers Using Recursive" - and there's nothing in your original post that reveals any need or relevance for an array. Dec 30, 2020 · Method Recursion (Sum Of 1st n Odd Numbers) By Ritwik Dubey Ritwik Dubey 1. Dec 19, 2013 · Power of a given number x raised to an exponent n is pow (x,n). If flag variable gets original value (which is true) back, then n is even. Else n is false. I just understand that it calls back the method. Here's my code so far: public static int countOdd(int[] numbers, int startIndex Nov 29, 2024 · In this article, we are going to learn how to check odd and even numbers using recursion in the C - c program to check odd or even May 24, 2020 · Consider the following recursive function in Collatz. import java. Jul 23, 2025 · Here, we are illustrating the total Sum using recursion can be done using storing numbers in an array, and taking the summation of all the numbers using recursion. Finally, we reconstruct the original array by placing all sorted odd numbers first, followed by the sorted even numbers. println ("Please input how many numbers will be used"); size=s. How do we handle large numbers? One simple improvement that we can do is use long long in C/C++ and long in Java/C#, but that does not help much as I have just been studying the concept of recursion and I thought that I would try a simple example. Example to Find Sum of N Natural Numbers: Input: N = 10 Output: Sum of first 10 Natural Number = 55 Input: N = 5 Output: Sum of first 5 Natural Number = 15 Methods to Find the Sum of N Natural Numbers in Java There are three methods to find Mar 17, 2025 · Given a number, we need to find sum of its digits using recursion. 7K subscribers Subscribed Mar 26, 2024 · - The recursion continues until the base case is reached, where the method returns true for odd numbers and false for even numbers. May 23, 2020 · I tried to write a method (for kicks) that would sum up the digits at even places using Java recursion. It receives two ints and it doesn't matter if they are positive or negative numbers. For example, the number 23495 would return 3+9 = 12. Then, we sort the odd numbers in descending order and the even numbers in ascending order. For function addOdd (n) write the missing recursive call. Please refer complete article on Merge Oct 14, 2014 · I am trying to write a method that finds how many odd numbers are between first position and last position. I was wondering if you could do the same thing except make the odd numbers appear first and then the even numbers afterward? I tried but to no avail. Jan 22, 2024 · In this program we are going to see how to find odd numbers in an Array by using Recursion in Java programming language. r] are sorted and merges the two sorted sub-arrays into one. it gives me the count as 2 – Scarl CommentedOct 8, 2013 at 5:26 Sep 9, 2018 · Recently I got assigned an assignment that says this: Write a program named NumberPermutation. The method accepts an array, and then two ints for the low and high position. Perfect for DSA practice! Jun 14, 2024 · Print Alternate Numbers in Java explores a fundamental programming task: generating and displaying alternate numbers in Java. Feb 8, 2023 · Importance of Learning How to Print Odd Numbers from 1 to 100 in Java Furthermore, learning how to print odd numbers from 1 to 100 in Java is essential for strengthening coding skills and problem-solving abilities. Understand the recursive approach and implement the algorithm to solve this problem efficiently. May 14, 2025 · Java Recursive methods: Exercises, Practice, Solution: Strengthen your recursion skills with these exercises in Java. This blog navigates through essential concepts and provides practical examples to help developers understand and implement this functionality effectively. Below is the implementation of this idea. Dec 6, 2014 · The original computes the sum of the first n odd numbers. // Without using recursion this could be simply: return val % 2 == 1. The best way to figure out how it works is to experiment with it. java, which is related to a famous unsolved problem in number theory, known as the Collatz problem or the 3n + 1 problem. Nov 15, 2020 · I'm new to programming and I am taking a course where I need to create a method in Java which rearranges an int array so all even integers come first and odd integers come second using recursion. Dec 14, 2022 · We will explain how to use a Java program to determine if a number is even or odd. Calculate factorials, sum numbers, check palindromes, generate permutations, and more. Write a java program using recursion to display all odd numbers from 1 to given number. Your algorithm computes the sum of all the odd numbers in the range 1. Enhance your problem-solving abilities through recursive thinking. Oct 9, 2020 · Here is the source code of the Java Program to Print even numbers in a given range using recursion. Learn how to print odd numbers up to n using recursion in Java. I am nearly done with the code. Java Program to Find Sum of all Odd Numbers between 0 to N Aug 3, 2009 · Although I have no problem whatsoever understanding recursion, I can't seem to wrap my head around the recursive solution to the Tower of Hanoi problem. Recursion is a programming concept where a function calls itself with a modified parameter until a base case is reached. Maybe you can clarifywhat the array is doing here? Java program to find sum of all odd numbers between 0 to N using for loop and recursion and with sample input and output. Scanner; class Question1 { public static void main (String []args) { Scanner s = new Scanner (System. If the current element at the required index is even then added to the sum else do not update the sum and again call the same method for the next index. The idea is to start with a boolean flag variable as true and switch it n times. // However, you must use recursion to implement this method, and cannot use % // You must correctly handle all integers, positive or negative. Dec 12, 2024 · So, practice frequently with these simple java programs examples and excel in coding the complex logic. Write a Java Program to find Sum of Odd Numbers in an Array using For Loop, While Loop, and Functions with example. Sep 9, 2010 · I understand the concept that the number of 1's in N is the same as N/2 if it's even, and N/2 + 1 if the number is odd, but I don't understand how to do it recursively. I have already coded the iterative method successfully that adds the sum of all odd numbers between n and m which are entered by the user. The elements May 14, 2025 · Java Recursive methods: Exercises, Practice, Solution: Strengthen your recursion skills with these exercises in Java. For example if user inputs 3, function returns 9 (1 + 3 + 5 = 9) int recursiveSumN Question: 5. Jan 22, 2024 · Prerequisite: Recursion in Java In the previous article, we have discussed about Java Program to Fins Sum of Digits of a Number by Using Recursion In this program we are going to see how to find odd numbers in an Array by using Recursion in Java programming language. Learn to calculate the sum of the first N odd numbers using recursion. It should have complexity of O(logN). (If you want a quicker way, then the formula n*n computes the sum of the first n odd numbers) Jul 23, 2025 · Merge Sort is a divide-and-conquer algorithm. Declare an integer variable say ‘ n ’ Prompt the user to enter the size of the array. Count Good Numbers in Python, Java, C++ and more. Examples: Input: N = 10 Output: 10 9 8 7 6 5 4 3 2 1 Input: N = 7 Output: 7 6 5 4 3 2 1 Approach 1: Run a loop from N to 1 and print the value of N for each iteration. Jan 19, 2024 · Output: The number of odd elements in the array are: 3 Method-2: Java Program to Find Odd Numbers in an Array by Using Recursion By Using User Input and Recursion Approach: Create a scanner class. in); int size, sum; System. Please refer Tail recursion for sum of array for details. Java Program to find Sum of Odd Numbers in an Array using For Loop This Java program allows the user to enter the size and Array elements. Java Recursion Recursion is the technique of making a function call itself. In the following code, I am attempting to take the numbers: 1, 2 JAVA Recursive method to test if a number is Odd? public boolean isOdd (int val) { // Return true if val is odd and false otherwise. n. Decrement the value of N by 1 after each iteration. This function should return the sum of all postive odd numbers less than or Mar 10, 2020 · Find the highest odd number in an array using recursion in java Asked 5 years, 1 month ago Modified 5 years, 1 month ago Viewed 1k times In this blog post, we will utilize recursion to print all odd numbers within a range. We can optimize the above recursive solution using tail recursion. Examples : Input: n = 11 Output: Odd Input: n = 10 Output: Even Method 1: Using Loop. Step-by-step guide and code examples included. Total odd numbers in the array A = 3. Apr 18, 2018 · I have to print the squares of n using recursion, and I have to print first the odd numbers squared in descending order, followed by the even numbers squared in ascending order. The program instead returns all the dig Jul 23, 2025 · Here, we are illustrating the total Sum using recursion can be done using storing numbers in an array, and taking the summation of all the numbers using recursion. It iterates through the array, accumulating odd numbers using recursion. Question: Q1. How a particular problem is solved using recursion? The idea is to represent a problem in terms of one or more smaller problems, and add one or more base conditions that stop the recursion. Complete solutions in C, C++, Java, and Python with detailed explanations. Q1. There are several methods. Mar 13, 2023 · Time Complexity: O (N) Auxiliary Space: O (1) Method #3: Recursion Get the number Get the remainder and pass the next remaining digits Get the rightmost digit of the number with help of the remainder '%' operator by dividing it by 10 and multiply it to the product. May 7, 2013 · It uses a method to sort out an array with even numbers coming out in the front and odd numbers in the back of the array. Using Hoare's Partition - O (n) Time and O (1) Space The Idea of the solution is based on Hoare's Partition Scheme of Quick Sort 1) Initialize two index variables lo and hi: lo = 0, hi = size -1 2) Keep incrementing lo index until we see an odd number. Oct 3, 2025 · Which approach is better - iterative or recursive? Iterative approach is better as the recursive approach requires extra space for recursion call stack and overhead of recursion calls. It divides the input array into two halves, calls itself the two halves, and then merges the two sorted halves. Using a recursive algorithm, certain problems can be solved quite easily. It also must use recursion. Sep 10, 2025 · Auxiliary Space: O (N), due to recursive function calls stored in the call stack. Feb 17, 2013 · I was also looking at it a different way, was going to select last 2 elements from array as went through recursion, take either the 1st or last number (odd/even) and add altogether at the end. Example: Recursive function `sumOfOddNumbers` calculates the sum of odd numbers in an array. It works by recursively dividing the input array into two halves, recursively sorting the two halves and finally merging them back together to obtain the sorted array. For instance, if it were {1,2,3,4,5,6}. I am unsuccessful and would appreciate Write a recursive method named numberSequence that accepts an integer n as a parameter and prints a sequence of n integers, descending from n to 1 and then ascending back from 1 to n as in the table below: Notice that for odd numbers the sequence has a single 1 in the middle while for even values it has two 1s in the middle. Learn Java recursion with step-by-step examples, clear explanations, and practical tips. Java Program to Find Odd Numbers in an Array by Using Recursion Lets assume there is an array say A which has 5 elements {77, 82 Q1. Aug 29, 2019 · Today I’ve faced with the following task: check whether the number is even or odd using the recursive function. Apr 29, 2019 · The program needs to take an odd number and output it in a descending order For example: if the input is 11 the output needs to be 11 , 9 , 7 , 5 , 3, 1. Here is the code from Wikipedia: procedure Files/Structures/DS To print number of Spaces,lines,characters and Tabs in a File Create a file with a set of numbers and write Odd and Even numbers into separate files Patterns Pyramids Games/Apps Read a Date and print the number of days elapsed from 1st January of the given year Program to run html file,to shutdown and to restart Right now the method above does n * n into infinity if I debug it, so it still works but I need this recursive method to stop after 10 times because my instructor requires us to find the exponent given a power of 10. This technique provides a way to break complicated problems down into simpler problems which are easier to solve. However writing a recursive code is always a fun exercise. This function should return the sum of all postive odd numbers less than or Java recursion May 31, 2022 · Given a number, check whether it is even or odd. Lets assume there is an array say A which has 5 elements {77, 82, 100, 17, 95} Odd numbers in the array A = 77, 17, 95. For function addOdd(n) write the missing recursive call. Better than official and forum solutions. Write a program in Java to print even or odd numbers in given range using recursion: Input the range to print starting from 1 : 10 Expected Output: All even numbers from 1 to 10 are : 2 4 6 8 10 All odd numbers from 1 to 10 are : 1 3 5 7 9 Oct 8, 2013 · java recursion edited Oct 8, 2013 at 5:38 Aashray 2,7631823 asked Oct 8, 2013 at 5:22 Scarl 95051732 The output should give me the count of even numbers, in my main method I have an array of length 4 and there are 3 even number. util. In-depth solution and explanation for LeetCode 1922. The merge (arr, l, m, r) is a key process that assumes that arr [l. out. I am new to coding in java and I wanted to test recursion. As of today, Java is the world's number one server programming language with a 12 million developer community, 5 million students studying worldwide and it's #1 choice for the cloud development. xsqfxe soqo gms gori4 9dsl bawcsw5 fm1ie55 ssug qjmat khln