Print first letter of each word in a string using regex (original) (raw)

Java Programs - Java Programming Examples In this article, we will learn and prepare for Interviews using Java Programming Examples. From basic Java programs like the Fibonacci series, Prime numbers, Factorial numbers, and Palindrome numbers to advanced Java programs. Java is one of the most popular programming languages today because of it 8 min read

Java Basic Programs

How to Read and Print an Integer Value in Java? The given task is to take an integer as input from the user and print that integer in Java. To read and print an integer value in Java, we can use the Scanner class to take input from the user. This class is present in the java.util package. Example input/output: Input: 357Output: 357 Input: 10Outpu 3 min read

Ways to Read Input from Console in Java In Java, there are four different ways to read input from the user in the command line environment(console). 1. Using Buffered Reader ClassBuffered Reader Class is the classical method to take input, Introduced in JDK 1.0. This method is used by wrapping the System.in (standard input stream) in an I 5 min read

Java Program to Multiply two Floating-Point Numbers The float class is a wrapper class for the primitive type float which contains several methods to effectively deal with a float value like converting it to a string representation, and vice-versa. An object of the Float class can hold a single float value. The task is to multiply two Floating point 1 min read

Java Program to Swap Two Numbers Problem Statement: Given two integers m and n. The goal is simply to swap their values in the memory block and write the java code demonstrating approaches. Illustration: Input : m=9, n=5Output : m=5, n=9 Input : m=15, n=5Output : m=5, n=15Here 'm' and 'n' are integer valueApproaches: There are 3 st 6 min read

Java Program to Add Two Binary Strings When two binary strings are added, then the sum returned is also a binary string. Example: Input : x = "10", y = "01" Output: "11"Input : x = "110", y = "011" Output: "1001" Explanation: 110 + 011 =1001Approach 1: Here, we need to start adding from the right side and when the sum returned is more th 3 min read

Java Program to Add two Complex Numbers Complex numbers are numbers that consist of two parts â€” a real number and an imaginary number. Complex numbers are the building blocks of more intricate math, such as algebra. The standard format for complex numbers is a + bi, with the real number first and the imaginary number last. General form fo 3 min read

Java Program to Check if a Given Integer is Odd or Even A number that is divisible by 2 and generates a remainder of 0 is called an even number. All the numbers ending with 0, 2, 4, 6, and 8 are even numbers. On the other hand, number that is not divisible by 2 and generates a remainder of 1 is called an odd number. All the numbers ending with 1, 3, 5,7, 7 min read

Java Program to Find the Largest of three Numbers Problem Statement: Given three numbers x, y, and z of which aim is to get the largest among these three numbers. Example:Â Input: x = 7, y = 20, z = 56Output: 56 // value stored in variable zFlowchart For Largest of 3 numbers: Algorithm to find the largest of three numbers: 1. Start2. Read the three 4 min read

Java Program to Find LCM of Two Numbers LCM (i.e. Least Common Multiple) is the largest of the two stated numbers that can be divided by both the given numbers. In this article, we will write a program to find the LCM in Java Java Program to Find the LCM of Two NumbersThe easiest approach for finding the LCM is to Check the factors and th 2 min read

Java Program to Find GCD or HCF of Two Numbers GCD (i.e. Greatest Common Divisor) or HCF (i.e. Highest Common Factor) is the largest number that can divide both the given numbers. Example: HCF of 10 and 20 is 10, and HCF of 9 and 21 is 3.Therefore, firstly find all the prime factors of both the stated numbers, then find the intersection of all t 2 min read

Java Program to Display All Prime Numbers from 1 to N For a given number N, the purpose is to find all the prime numbers from 1 to N. Examples: Input: N = 11Output: 2, 3, 5, 7, 11Input: N = 7Output: 2, 3, 5, 7 Approach 1: Firstly, consider the given number N as input.Then apply a for loop in order to iterate the numbers from 1 to N.At last, check if ea 4 min read

Java Program to Find if a Given Year is a Leap Year Leap Year contains 366 days, which comes once every four years. In this article, we will learn how to write the leap year program in Java. Facts about Leap YearEvery leap year corresponds to these facts : A century year is a year ending with 00. A century year is a leap year only if it is divisible 5 min read

Java Program to Check Armstrong Number between Two Integers A positive integer with digits p, q, r, sâ€¦, is known as an Armstrong number of order n if the following condition is fulfilled. pqrs... = pn + qn + rn + sn +....Example: 370 = 3*3*3 + 7*7*7 + 0 = 27 + 343 + 0 = 370Therefore, 370 is an Armstrong number. Examples: Input : 100 200 Output :153 Explanati 2 min read

Java Program to Check If a Number is Neon Number or Not A neon number is a number where the sum of digits of the square of the number is equal to the number. The task is to check and print neon numbers in a range. Illustration: Case 1: Input : 9 Output : Given number 9 is Neon number Explanation : square of 9=9*9=81; sum of digit of square : 8+1=9(which 4 min read

Java Program to Check Whether the Character is Vowel or Consonant In this article, we are going to learn how to check whether a character is a vowel or a consonant. So, the task is, for any given character, we need to check if it is a vowel or a consonant. As we know, vowels are â€˜aâ€™, â€˜eâ€™, â€˜iâ€™, â€˜oâ€™, â€˜uâ€™ and all the other characters (i.e. â€˜bâ€™, â€˜câ€™, â€˜dâ€™, â€˜fâ€™ â€¦..) are 4 min read

Java Program for Factorial of a Number The factorial of a non-negative integer is multiplication of all integers smaller than or equal to n. In this article, we will learn how to write a program for the factorial of a number in Java. Formulae for Factorialn! = n * (n-1) * (n-2) * (n-3) * ........ * 1 Example: 6! == 6*5*4*3*2*1 = 720. 5! 4 min read

Java Program to Find Sum of Fibonacci Series Numbers of First N Even Indexes For a given positive integer N, the purpose is to find the value of F2 + F4 + F6 +â€¦â€¦â€¦+ F2n till N number. Where Fi indicates the i'th Fibonacci number. The Fibonacci Series is the numbers in the below-given integer sequence. 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, â€¦â€¦Examples: Input: n = 4 Output: 3 4 min read

Java Program to Calculate Simple Interest Simple interest is a quick method of calculating the interest charge on a loan. Simple interest is determined by multiplying the daily interest rate by the principal by the number of days that elapse between payments. Simple interest formula is given by: Simple Interest = (P x T x R)/100 Where, P is 2 min read

Java Program for compound interest Compound Interest formula: Formula to calculate compound interest annually is given by: Compound Interest = P(1 + R/100)t Where, P is principal amount R is the rate and T is the time span Example: Input : Principal (amount): 1200 Time: 2 Rate: 5.4 Output : Compound Interest = 1333.099243 Java Code / 1 min read

Java Program to Find the Perimeter of a Rectangle A Rectangle is a quadrilateral with four right angles (90Â°). In a rectangle, the opposite sides are equal. A rectangle with all four sides equal is called a Square. A rectangle can also be called as right angled parallelogram. In the above rectangle, the sides A and C are equal and B and D are equal 2 min read

Java Pattern Programs

Java Program to Print Right Triangle Star Pattern In this article, we will learn about printing Right Triangle Star Pattern. Examples: Input : n = 5 Output: * * * * * * * * * * * * * * * Right Triangle Star Pattern: Java Code import java.io.*; // Java code to demonstrate right star triangle public class GeeksForGeeks { // Function to demonstrate pr 5 min read

Java Program to Print Left Triangle Star Pattern In this article, we will learn about printing Left Triangle Star Pattern. Examples: Input : n = 5 Output: * * * * * * * * * * * * * * * Left Triangle Star Pattern: Java Code import java.io.*; // java program for left triangle public class GFG { // Function to demonstrate printing pattern public stat 5 min read

Java Program to Print Pyramid Number Pattern Here we are getting a step ahead in printing patterns as in generic we usually play with columnar printing in the specific row keep around where elements in a row are either added up throughout or getting reduced but as we move forward we do start playing with rows which hold for outer loop in our p 2 min read

Java Program to Print Reverse Pyramid Star Pattern Approach: 1. Get the number of input rows from the user using Scanner Class or BufferedReader Class object. 2. Now run two loops Outer loop to iterate through a number of rows as initialized or input is taken from reader class object in java. Now,Run an inner loop from 1 to 'i-1'Ru another inner loo 4 min read

Java Program to Print Upper Star Triangle Pattern The upper star triangle pattern means the base has to be at the bottom and there will only be one star to be printed in the first row. Here is the issue that will arise is what way we traverse be it forward or backward we can't ignore the white spaces, so we are not able to print a star in the first 2 min read

Java Program to Print Mirror Upper Star Triangle Pattern The pattern has two parts - both mirror reflections of each other. The base of the triangle has to be at the bottom of the imaginary mirror and the tip at the top. Illustration: Input: size = 7 Output: * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 5 min read

Java Program to Print Downward Triangle Star Pattern Downward triangle star pattern means we want to print a triangle that is downward facing means base is upwards and by default, orientation is leftwards so the desired triangle to be printed should look like * * * * * * * * * * Example Java Code // Java Program to Print Lower Star Triangle Pattern // 2 min read

Java Program to Print Mirror Lower Star Triangle Pattern In this article, we are going to learn how to print mirror lower star triangle patterns in Java. Illustration: Input: number = 7 Output: * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Methods: We can print mirror lower star triangle pa 5 min read

Java Program to Print Star Pascalâ€™s Triangle Pascalâ€™s triangle is a triangular array of the binomial coefficients. Write a function that takes an integer value n as input and prints the first n lines of Pascalâ€™s triangle. Following are the first 6 rows of Pascalâ€™s Triangle.In this article, we will look into the process of printing Pascal's tri 4 min read

Java Program to Print Diamond Shape Star Pattern In this article, we are going to learn how to print diamond shape star patterns in Java. Illustration: Input: number = 7 Output: * *** ***** ******* ********* *********** ************* *********** ********* ******* ***** *** * Methods: When it comes to pattern printing we do opt for standard ways of 6 min read

Java Program to Print Square Star Pattern Here, we will implement a Java program to print the square star pattern. We will print the square star pattern with diagonals and without diagonals. Example: ********************** * * * * * * * * * * * * ********************** Approach: Step 1: Input number of rows and columns. Step 2: For rows of 4 min read

Java Program to Print Pyramid Star Pattern This article will guide you through the process of printing a Pyramid star pattern in Java. 1. Simple pyramid pattern Java Code import java.io.*; // Java code to demonstrate Pyramid star patterns public class GeeksForGeeks { // Function to demonstrate printing pattern public static void PyramidStar( 5 min read

Java Program to Print Spiral Pattern of Numbers Given a number n as the size of the matrix, the task is to print a spiral pattern of size n. Examples: Input : n = 4 Output: 1 2 3 4 12 13 14 5 11 16 15 6 10 9 8 7 Preview of the Spiral Pattern: Java Code public class GFG { public static void printSpiral(int size) { // Create row and col // to trave 3 min read

Java Conversion Programs

Java Program to Convert Binary to Octal A Binary (base 2) number is given, and our task is to convert it into an Octal (base 8) number. There are different ways to convert binary to decimal, which we will discuss in this article. Example of Binary to Octal Conversion: Input : 100100Output: 44 Input : 1100001Output : 141 A Binary Number Sy 5 min read

Java Program to Convert Octal to Decimal Octal numbers are numbers with 8 bases and use digits from 0-7. This system is a base 8 number system. The decimal numbers are the numbers with 10 as their base and use digits from 0-9 to represent the decimal number. They also require dots to represent decimal fractions. We have to convert a number 3 min read

Java Program For Decimal to Octal Conversion Given a decimal number N, convert N into an equivalent octal number, i.e., convert the number with base value 10 to base value 8. The decimal number system uses 10 digits from 0-9, and the octal number system uses 8 digits from 0-7 to represent any numeric value. Illustration: Basic input/output for 3 min read

Java Program for Hexadecimal to Decimal Conversion Given a Hexadecimal (base 16) number N, and our task is to convert the given Hexadecimal number to a Decimal (base 10). The hexadecimal number uses the alpha-numeric values 0-9 and A- F. And the decimal number uses the numeric values 0-9. Example: Input : 1ABOutput: 427Input : 1AOutput: 26 Approach 3 min read

Java Program For Decimal to Hexadecimal Conversion Given a decimal number N, convert N into an equivalent hexadecimal number i.e. convert the number with base value 10 to base value 16. The decimal number system uses 10 digits 0-9 and the Hexadecimal number system uses 0-9, A-F to represent any numeric value. Examples of Decimal to Hexadecimal Conve 3 min read

Java Program for Decimal to Binary Conversion Given a decimal number as input, we need to write a program to convert the given decimal number into an equivalent binary number. Examples:Â Input : 7Output : 111 Input: 33Output: 100001 Binary-to-decimal conversion is done to convert a number given in the binary system to its equivalent in the deci 5 min read

Java Program for Decimal to Binary Conversion Given a decimal number as input, we need to write a program to convert the given decimal number into an equivalent binary number. Examples:Â Input : 7Output : 111 Input: 33Output: 100001 Binary-to-decimal conversion is done to convert a number given in the binary system to its equivalent in the deci 5 min read

Boolean toString() Method in Java In Java, the toString() method of the Boolean class is a built-in method to return the Boolean value in string format. The Boolean class is a part of java.lang package. This method is useful when we want the output in the string format in places like text fields, console output, or simple text forma 2 min read

Convert String to Double in Java In this article, we will convert a String to a Double in Java. There are three methods for this conversion from String to Double, as mentioned below in the article. Methods for String-to-Double ConversionDifferent ways for converting a String to a Double are mentioned below: Using the parseDouble() 3 min read

Java Program to Convert Double to String The primary goal of double to String conversion in Java is to store big streams of numbers that are coming where even data types fail to store the stream of numbers. It is generically carried out when we want to display the bigger values. In this article, we will learn How to Convert double to Strin 3 min read

Java Program to Convert String to Long To convert a String to Long in Java, we can use built-in methods provided by the Long class. In this article, we will learn how to convert String to Long in Java with different methods. Example: In the below example, we use the most common method i.e. Long.parseLong() method to convert a string to a 3 min read

Java Program to Convert Long to String The long to String conversion in Java generally comes in need when we have to display a long number in a GUI application because everything is displayed in string form. In this article, we will learn about Java Programs to convert long to String. Given a Long number, the task is to convert it into a 4 min read

Java Program For Int to Char Conversion In this article, we will check how to convert an Int to a Char in Java. In Java, char takes 2 bytes (16-bit UTF encoding ), while int takes 4 bytes (32-bit). So, if we want the integer to get converted to a character then we need to typecast because data residing in 4 bytes cannot get into a single 3 min read

Java Program to Convert Char to Int Given a char value, and our task is to convert it into an int value in Java. We can convert a Character to its equivalent Integer in different ways, which are covered in this article. Examples of Conversion from Char to Int: Input : ch = '3'Output : 3 Input : ch = '9'Output : 9 The char data type is 4 min read

Java Classes and Object Programs

Classes and Objects in Java In Java, classes and objects are basic concepts of Object Oriented Programming (OOPs) that are used to represent real-world concepts and entities. The class represents a group of objects having similar properties and behavior, or in other words, we can say that a class is a blueprint for objects, wh 12 min read

Abstract Class in Java In Java, abstract class is declared with the abstract keyword. It may have both abstract and non-abstract methods(methods with bodies). An abstract is a Java modifier applicable for classes and methods in Java but not for Variables. In this article, we will learn the use of abstract classes in Java. 10 min read

Singleton Method Design Pattern in Java In object-oriented programming, a Java singleton class is a class that can have only one object (an instance of the class) at a time. After the first time, if we try to instantiate the Java Singleton classes, the new variable also points to the first instance created. So, whatever modifications we d 8 min read

Java Interface An Interface in Java programming language is defined as an abstract type used to specify the behaviour of a class. An interface in Java is a blueprint of a behaviour. A Java interface contains static constants and abstract methods. Key Properties of Interface: The interface in Java is a mechanism to 13 min read

Encapsulation in Java Encapsulation is one of the core concepts in Java Object-Oriented Programming (OOP). It is the process of wrapping data (variables) and methods that operate on the data into a single unit, i.e., a class. Encapsulation is used to hide the internal implementation details of a class. This technique ens 10 min read

Inheritance in Java Java Inheritance is a fundamental concept in OOP(Object-Oriented Programming). It is the mechanism in Java by which one class is allowed to inherit the features(fields and methods) of another class. In Java, Inheritance means creating new classes based on existing ones. A class that inherits from an 14 min read

Abstraction in Java Abstraction in Java is the process of hiding the implementation details and only showing the essential details or features to the user. It allows to focus on what an object does rather than how it does it. The unnecessary details are not displayed to the user. Key features of abstraction: Abstractio 10 min read

Difference Between Data Hiding and Abstraction in Java Abstraction Is hiding the internal implementation and just highlight the set of services. It is achieved by using the abstract class and interfaces and further implementing the same. Only necessarily characteristics of an object that differentiates it from all other objects. Only the important detai 6 min read

Polymorphism in Java Polymorphism in Java is one of the core concepts in object-oriented programming (OOP) that allows objects to behave differently based on their specific class type. The word polymorphism means having many forms, and it comes from the Greek words poly (many) and morph (forms), this means one entity ca 7 min read

Method Overloading in Java In Java, Method Overloading allows us to define multiple methods with the same name but different parameters within a class. This difference can be in the number of parameters, the types of parameters, or the order of those parameters. Method overloading in Java is also known as Compile-time Polymor 10 min read

Overriding in Java Overriding in Java occurs when a subclass or child class implements a method that is already defined in the superclass or base class. When a subclass provides its own version of a method that is already defined in its superclass, we call it method overriding. The subclass method must match the paren 15 min read

Super Keyword in Java The super keyword in Java is a reference variable that is used to refer to the parent class when we are working with objects. You need to know the basics of Inheritance and Polymorphism to understand the Java super keyword. The Keyword "super" came into the picture with the concept of Inheritance. I 8 min read

'this' reference in Java In Java, 'this' is a reference variable that refers to the current object, or can be said "this" in Java is a keyword that refers to the current object instance. It can be used to call current class methods and fields, to pass an instance of the current class as a parameter, and to differentiate bet 6 min read

static Keyword in Java The static keyword in Java is mainly used for memory management. The static keyword in Java is used to share the same variable or method of a given class. The users can apply static keywords with variables, methods, blocks, and nested classes. The static keyword belongs to the class rather than an i 9 min read

Access Modifiers in Java In Java, access modifiers are essential tools that define how the members of a class, like variables, methods, and even the class itself can be accessed from other parts of our program. They are an important part of building secure and modular code when designing large applications. Understanding de 7 min read

Java Methods Programs

Java main() Method - public static void main(String[] args) Java's main() method is the starting point from where the JVM starts the execution of a Java program. JVM will not execute the code if the program is missing the main method. Hence, it is one of the most important methods of Java, and having a proper understanding of it is very important. The Java c 6 min read

Difference between static and non-static method in Java A static method is a method that belongs to a class, but it does not belong to an instance of that class and this method can be called without the instance or object of that class. Every method in java defaults to a non-static method without static keyword preceding it. Non-static methods can access 6 min read

HashTable forEach() method in Java with Examples The forEach(BiConsumer) method of Hashtable class perform the BiConsumer operation on each entry of hashtable until all entries have been processed or the action throws an exception. The BiConsumer operation is a function operation of key-value pair of hashtable performed in the order of iteration. 2 min read

StringBuilder toString() method in Java with Examples The toString() method of the StringBuilder class is the inbuilt method used to return a string representing the data contained by StringBuilder Object. A new String object is created and initialized to get the character sequence from this StringBuilder object and then String is returned by toString( 3 min read

StringBuffer codePointAt() method in Java with Examples The codePointAt() method of StringBuffer class returns a character Unicode point at that index in sequence contained by StringBuffer. This method returns the â€œUnicodenumberâ€ of the character at that index. Value of index must be lie between 0 to length-1. If the char value present at the given index 2 min read

How compare() method works in Java Prerequisite: Comparator Interface in Java, TreeSet in JavaThe compare() method in Java compares two class specific objects (x, y) given as parameters. It returns the value: 0: if (x==y)-1: if (x < y)1: if (x > y)Syntax: public int compare(Object obj1, Object obj2)where obj1 and obj2 are the t 3 min read

Short equals() method in Java with Examples The equals() method of Short class is a built in method in Java which is used to compare the equality given Object with the instance of Short invoking the equals() method. Syntax ShortObject.equals(Object a) Parameters: It takes an Object type object a as input which is to be compared with the insta 2 min read

Difference Between next() and hasNext() Method in Java Collections In Java, objects are stored dynamically using objects. Now in order to traverse across these objects is done using a for-each loop, iterators, and comparators. Here will be discussing iterators. The iterator interface allows visiting elements in containers one by one which indirectly signifies retri 3 min read

What does start() function do in multithreading in Java? We have discussed that Java threads are typically created using one of the two methods : (1) Extending thread class. (2) Implementing RunnableIn both the approaches, we override the run() function, but we start a thread by calling the start() function. So why don't we directly call the overridden ru 2 min read

Java Thread.start() vs Thread.run() Method In Java's multi-threading concept, start() and run() are the two most important methods. In this article, we will learn the main differences between Thread.start() and Thread.run() in Java. Thread.start() vs Thread.run() MethodThread.start()Thread.run()Creates a new thread and the run() method is ex 4 min read

Java Searching Programs

Java Program for Linear Search Linear Search is the simplest searching algorithm that checks each element sequentially until a match is found. It is good for unsorted arrays and small datasets. Given an array a[] of n elements, write a function to search for a given element x in a[] and return the index of the element where it is 2 min read

Binary Search in Java Binary search is a highly efficient searching algorithm used when the input is sorted. It works by repeatedly dividing the search range in half, reducing the number of comparisons needed compared to a linear search. Here, we are focusing on finding the middle element that acts as a reference frame t 7 min read

Java Program To Recursively Linearly Search An Element In An Array Given an array arr[] of n elements, write a recursive function to search for a given element x in the given array arr[]. If the element is found, return its index otherwise, return -1. Input/Output Example: Input : arr[] = {25, 60, 18, 3, 10}, Element to be searched x = 3Output : 3 (index )Input : a 3 min read

Java 1-D Array Programs

Check If a Value is Present in an Array in Java Given an array of Integers and a key element. Our task is to check whether the key element is present in the array. If the element (key) is present in the array, return true; otherwise, return false. Example: Input: arr[] = [3, 5, 7, 2, 6, 10], key = 7Output: Is 7 present in the array: trueInput: ar 8 min read

Java Program to Find Largest Element in an Array Finding the largest element in an array is a common programming task. There are multiple approaches to solve it. In this article, we will explore four practical approaches one by one to solve this in Java. Example Input/Output: Input: arr = { 1, 2, 3, 4, 5}Output: 5 Input: arr = { 10, 3, 5, 7, 2, 12 4 min read

Arrays.sort() in Java The Arrays.sort() method is used for sorting the elements in an Array. It has two main variations: Sorting the entire array (it may be an integer or character array) Sorting a specific range by passing the starting and ending indices.Below is a simple example that uses the sort() method to arrange a 6 min read

Java Program to Sort the Elements of an Array in Descending Order Here, we will sort the array in descending order to arrange elements from largest to smallest. The simple solution is to use Collections.reverseOrder() method. Another way is sorting in ascending order and reversing. 1. Using Collections.reverseOrder()In this example, we will use Collections.reverse 2 min read

Java Program to Sort the Elements of an Array in Ascending Order Here, we will sort the array in ascending order to arrange elements from smallest to largest, i.e., ascending order. So the easy solution is that we can use the Array.sort method. We can also sort the array using Bubble sort. 1. Using Arrays.sort() MethodIn this example, we will use the Arrays.sort( 2 min read

Remove duplicates from Sorted Array Given a sorted array arr[] of size n, the goal is to rearrange the array so that all distinct elements appear at the beginning in sorted order. Additionally, return the length of this distinct sorted subarray. Note: The elements after the distinct ones can be in any order and hold any value, as they 7 min read

Java Program to Merge Two Arrays Given two arrays, the task is to merge or concatenate them and store the result into another array. Example: [GFGTABS] Java // Java Program to demonstrate merging // two array using System.arraycopy() method import java.util.Arrays; public class MergeTwoArrays1 { public static void main(String[] arg 5 min read

Java Program to Check if two Arrays are Equal or not In Java, comparing two arrays means checking if they have the same length and identical elements. This checking process ensures that both arrays are equivalent in terms of content and structure. Example: In Java, the simplest way to check if two arrays are equal in Java is by using the built-in Arra 4 min read

Remove all Occurrences of an Element from Array in Java In Java, removing all occurences of a given element from an array can be done using different approaches that are, Naive approach using array copyJava 8 StreamsUsing ArrayList.removeAll()Using List.removeIf()Problem Stament: Given an array and a key, the task is to remove all occurrences of the spec 5 min read

Java Program to Find Common Elements Between Two Arrays Given two arrays and our task is to find their common elements. Examples:Input: Array1 = ["Article", "for", "Geeks", "for", "Geeks"], Array2 = ["Article", "Geeks", "Geeks"]Output: [Article, Geeks] Input: Array1 = ["a", "b", "c", "d", "e", "f"], Array2 = ["b", "d", "e", "h", "g", "c"]Output: [b, c, d 4 min read

Array Copy in Java In Java, copying an array can be done in several ways, depending on our needs such as shallow copy or deep copy. In this article, we will learn different methods to copy arrays in Java. Example: Assigning one array to another is an incorrect approach to copying arrays. It only creates a reference to 6 min read

Java Program to Left Rotate the Elements of an Array In Java, left rotation of an array involves shifting its elements to the left by a given number of positions, with the first elements moving around to the end. There are different ways to left rotate the elements of an array in Java. Example: We can use a temporary array to rotate the array left by 5 min read

Java 2-D Arrays (Matrix) Programs

Print a 2D Array or Matrix in Java In this article, we will learn to Print 2 Dimensional Matrix. 2D-Matrix or Array is a combination of Multiple 1 Dimensional Arrays. In this article we cover different methods to print 2D Array. When we print each element of the 2D array we have to iterate each element so the minimum time complexity 4 min read

Java Program to Add two Matrices Given two matrices A and B of the same size, the task is to add them in Java. Examples: Input: A[][] = {{1, 2}, {3, 4}} B[][] = {{1, 1}, {1, 1}} Output: {{2, 3}, {4, 5}} Input: A[][] = {{2, 4}, {3, 4}} B[][] = {{1, 2}, {1, 3}} Output: {{3, 6}, {4, 7}} Program to Add Two Matrices in JavaFollow the St 2 min read

Sorting a 2D Array according to values in any given column in Java We are given a 2D array of order N X M and a column number K ( 1<=K<=m). Our task is to sort the 2D array according to values in Column K. Examples: Input: If our 2D array is given as (Order 4X4) 39 27 11 42 10 93 91 90 54 78 56 89 24 64 20 65 Sorting it by values in column 3 Output: 39 27 11 3 min read

Java Program to Check if two Arrays are Equal or not In Java, comparing two arrays means checking if they have the same length and identical elements. This checking process ensures that both arrays are equivalent in terms of content and structure. Example: In Java, the simplest way to check if two arrays are equal in Java is by using the built-in Arra 4 min read

Java Program to Find Transpose of Matrix Transpose of a matrix is obtained by changing rows to columns and columns to rows. In other words, the transpose of A[ ][ ] is obtained by changing A[i][j] to A[j][i]. Example of First Transpose of MatrixInput: [ [ 1 , 2 , 3 ] , [ 4 , 5 , 6 ] , [ 7 , 8 , 9 ] ]Output: [ [ 1 , 4 , 7 ] , [ 2 , 5 , 8 ] 5 min read

Java Program to Find the Determinant of a Matrix The determinant of a matrix is a special calculated value that can only be calculated if the matrix has same number of rows and columns (square matrix). It is helpful in determining the system of linear equations, image processing, and determining whether the matrix is singular or non-singular. In t 5 min read

Java Program to Find the Normal and Trace of a Matrix For a given 2D matrix, the purpose is to find the Trace and Normal of the matrix. In this article, we will learn about Normal and Trace of a Matrix in Java. Examples : Input : matrix[][] = {{1, 4, 4}, {2, 3, 7}, {0, 5, 1}}; Output : Normal = 11 Trace = 5 Explanation : Normal = sqrt(1*1+ 4*4 + 4*4 + 3 min read

Java Program to Print Boundary Elements of the Matrix Given a matrix of size Row x Col Print the boundary elements of the matrix. Boundary elements are those elements which are not surrounded by elements on all four directions, i.e. elements in the first row, first column, last row and last column. Example: Input : 1 2 3 4 5 6 7 8 9 Output: 1 2 3 4 6 7 2 min read

Java Program to Rotate Matrix Elements A matrix is simply a two-dimensional array. So, the goal is to deal with fixed indices at which elements are present and to perform operations on indexes such that elements on the addressed should be swapped in such a manner that it should look out as the matrix is rotated. For a given matrix, the t 6 min read

Java Program to Compute the Sum of Diagonals of a Matrix For a given 2D square matrix of size N*N, the task is to find the sum of elements in the Principal and Secondary diagonals. For example, analyze the following 4 Ã— 4 input matrix. a00 a01 a02 a03a10 a11 a12 a13a20 a21 a22 a23a30 a31 a32 a33 Example: Input 1 : 6 7 3 4 8 9 2 1 1 2 9 6 6 5 7 2Output 1 : 4 min read

Java Program to Interchange Elements of First and Last in a Matrix Across Rows For a given 4 Ã— 4 matrix, the task is to interchange the elements of the first and last rows and then return the resultant matrix. Illustration: Input 1: 1 1 5 0 2 3 7 2 8 9 1 3 6 7 8 2 Output 1: 6 7 8 2 2 3 7 2 8 9 1 3 1 1 5 0 Input 2: 7 8 9 10 11 13 14 1 15 7 12 22 11 21 30 1 Output 2: 11 21 30 1 3 min read

Java Program to Interchange Elements of First and Last in a Matrix Across Columns For a given 4 x 4 matrix, the task is to interchange the elements of the first and last columns and then return the resultant matrix. Example Test Case for the ProblemInput : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Output : 4 2 3 1 8 6 7 5 12 10 11 9 16 14 15 13 Implementation of Interchange Elements 2 min read

Java String Programs

Java Program to Get a Character from a String Given a String str, the task is to get a specific character from that String at a specific index. Examples: Input: str = "Geeks", index = 2Output: eInput: str = "GeeksForGeeks", index = 5Output: F Below are various ways to do so: Using String.charAt() method: Get the string and the indexGet the spec 5 min read

Replace a character at a specific index in a String in Java In Java, here we are given a string, the task is to replace a character at a specific index in this string. Examples of Replacing Characters in a StringInput: String = "Geeks Gor Geeks", index = 6, ch = 'F'Output: "Geeks For Geeks."Input: String = "Geeks", index = 0, ch = 'g'Output: "geeks"Methods t 3 min read

Reverse a String in Java In Java, reversing a string means reordering the string characters from the last to the first position. Reversing a string is a common task in many Java applications and can be achieved using different approaches. In this article, we will discuss multiple approaches to reverse a string in Java with 7 min read

Java Program to Reverse a String using Stack The Stack is a linear data structure that follows the LIFO(Last In First Out) principle, i.e, the element inserted at the last is the element to come out first. Approach: Push the character one by one into the Stack of datatype character.Pop the character one by one from the Stack until the stack be 2 min read

Sort a String in Java (2 different ways) The string class doesn't have any method that directly sorts a string, but we can sort a string by applying other methods one after another. The string is a sequence of characters. In java, objects of String are immutable which means a constant and cannot be changed once created. Creating a String T 6 min read

Swapping Pairs of Characters in a String in Java Given string str, the task is to write a Java program to swap the pairs of characters of a string. If the string contains an odd number of characters then the last character remains as it is. Examples: Input: str = â€œJavaâ€Output: aJav Explanation: The given string contains even number of characters. 3 min read

Check if a given string is Pangram in Java Given string str, the task is to write Java Program check whether the given string is a pangram or not. A string is a pangram string if it contains all the character of the alphabets ignoring the case of the alphabets. Examples: Input: str = "Abcdefghijklmnopqrstuvwxyz"Output: YesExplanation: The gi 3 min read

Print first letter of each word in a string using regex Given a string, extract the first letter of each word in it. "Words" are defined as contiguous strings of alphabetic characters i.e. any upper or lower case characters a-z or A-Z. Examples: Input : Geeks for geeksOutput :Gfg Input : United KingdomOutput : UKBelow is the Regular expression to extract 3 min read

Java Program to Determine the Unicode Code Point at Given Index in String ASCII is a code that converts the English alphabets to numerics as numeric can convert to the assembly language which our computer understands. For that, we have assigned a number against each character ranging from 0 to 127. Alphabets are case-sensitive lowercase and uppercase are treated different 5 min read

Remove Leading Zeros From String in Java Given a string of digits, remove leading zeros from it. Illustrations: Input : 00000123569Output: 123569 Input: 000012356090Output: 12356090 Approach: We use the StringBuffer class as Strings are immutable. Count leading zeros by iterating string using charAt(i) and checking for 0 at the "i" th indi 3 min read

Compare two Strings in Java String in Java are immutable sequences of characters. Comparing strings is the most common task in different scenarios such as input validation or searching algorithms. In this article, we will learn multiple ways to compare two strings in Java with simple examples. Example: To compare two strings i 4 min read

Compare two strings lexicographically in Java In this article, we will discuss how we can compare two strings lexicographically in Java. One solution is to use Java compareTo() method. The method compareTo() is used for comparing two strings lexicographically in Java. Each character of both the strings is converted into a Unicode value for comp 3 min read

Java program to print Even length words in a String Given a string s, write a Java program to print all words with even length in the given string. Example to print even length words in a String Input: s = "i am Geeks for Geeks and a Geek" Output: am Geek Example: [GFGTABS] Java // Java program to print // even length words in a string class GfG { pu 3 min read

Insert a String into another String in Java Given a String, the task is to insert another string in between the given String at a particular specified index in Java. Examples: Input: originalString = "GeeksGeeks", stringToBeInserted = "For", index = 4 Output: "GeeksForGeeks" Input: originalString = "Computer Portal", stringToBeInserted = "Sci 4 min read

Split a String into a Number of Substrings in Java Given a String, the task it to split the String into a number of substrings. A String in java can be of 0 or more characters. Examples : (a) "" is a String in java with 0 character (b) "d" is a String in java with 1 character (c) "This is a sentence." is a string with 19 characters. Substring: A Str 5 min read