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To calculate the power of a number, Java provides different ways to do this using loops, built-in methods, and recursion. In this article, we will learn how to calculate the power of a number using recursion. In Java, Recursion is a process in which a function calls itself multiple times until it reaches a base condition, and the corresponding function is called a recursive function. Problem Statement Given a base number and a power value, we need to calculate the result of raising the base to the power using recursion. Below is a demonstration of the same. Input: Enter ... Read More
In this article, we will understand how to find the factorial of a number using recursion in Java. The factorial of a positive number is the product of the number itself and all descending positive integers up to "n". The factorial of a negative number does not exist, and the factorial of 0 is 1. The factorial of a positive number is - factorial of n (n!) = 1 * 2 * 3 * 4 * ... * n Factorial Using a Recursive Function A recursive function is a function that calls itself multiple times until a particular condition is satisfied. ... Read More
In this article, we will understand how to get input from the user in Java. Java provides a built-in Scanner Class that belongs to the java.util package. The Scanner class is used to get user input. In this article, we will learn how to take different types of input, like integers, floating numbers, strings, etc., from the user in Java. Algorithm Following are the steps to get input from the user - Step 1- START Step-2- Import the Scanner class Step 3- Create a Scanner object Step 4- Prompt the user to enter ... Read More
Java HashMap is a hash table-based implementation of Java's Map interface. It is a collection of key-value pairs. In this article, we will understand how to get a key from a HashMap using the value. Following are the ways to get a key from a HashMap using the value: Using For Loop Using Stream API Using For Loop We can iterate through the entries of the HashMap using a for loop and check if the value matches the one we are looking for. If it does, we return the corresponding ... Read More
In this article, we will understand how to check if a Set is a subset of another set. A Set is a Collection that cannot contain duplicate elements. It models the mathematical set abstraction. The Set interface contains only methods inherited from Collection and adds the restriction that duplicate elements are not allowed. Following are the ways to check if a set is a subset of another set: Using containsAll() Method Using Stream API Using containsAll() Method In Java, the set interface has a method called containsAll() that checks ... Read More
The ArrayList is a resizable array, which is part of java.util package. The difference between a built-in array and an ArrayList in Java is that the size of an array cannot be modified. In this article, we will understand how to pass an ArrayList as a function argument. Following are the ways to pass an ArrayList as a function argument: Using Function Argument Using Return Type Using Function Argument We can pass an ArrayList as a function argument in Java. The function can take an ArrayList as a parameter and perform operations ... Read More
In this article, we will learn how to convert the local time to GMT (Greenwich Mean Time) in Java. We need this conversion when we want to standardize time across different time zones or when working with systems that require GMT. We will cover the following methods to convert local time to GMT: Using ZonedDateTime class Using Calendar Class Using Date Class Using ZonedDateTime Class ZonedDateTime class was introduced in Java 8, which is used for converting local time to GMT. We can use the ... Read More
List Interface is a collection in Java that is used for storing elements in a sequence. It also allows us to save duplicates as well as null values. In this article, we will learn how to empty a list in Java. Following are the ways to empty a list in Java: Using clear() Method Using removeAll() Method Using clear() Method The clear() method of the List interface is used to remove all elements from the list. It removes all the elements but returns nothing. Following is the syntax of the ... Read More
A Set is a Collection that cannot contain duplicate elements (same as the mathematical set abstraction). The Set interface contains only methods inherited from Collection and adds the restriction that duplicate elements are prohibited. Finding the difference between two sets means finding the elements that are not similar in both sets. For example, we have set A = {1, 2, 3} and set B = {2, 3, 4}. The difference between these two sets will be {1, 4} because 1 is not in set B and 4 is not in set A. In this article, we will learn how to ... Read More
HashMap is a part of the Java Collections Framework, and it is used for storing key-value pairs. In this article, we will see how to update the value of a HashMap using a key. We will use following methods to update the value of a HashMap: Using put() Method Using compute() Method Using replace() Method Using put() Method The put() method is used to add a key-value pair to the HashMap. If the key already exists, it will update the value that is stored with that ... Read More