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To separate zeros from non-zeros in an integer array, and push them to the end, you need to rearrange it array by assigning all the nonzero elements to its positions, sequentially, starting from zero. Then, from last position of the array to its end populate it with zeros.ExampleFollowing Java program pushes all the zeros in an array to its end.import java.util.Arrays; import java.util.Scanner; public class ZerosFromNonZeros { public static void main(String args[]){ //Reading the array from the user Scanner sc = new Scanner(System.in); System.out.println("Enter the size of the array that ... Read More
To find all pairs of elements in Java array whose sum is equal to a given number −Add each element in the array to all the remaining elements (except itself).Verify if the sum is equal to the required number.If true, print their indices.Exampleimport java.util.Arrays; import java.util.Scanner; public class sample { public static void main(String args[]){ //Reading the array from the user Scanner sc = new Scanner(System.in); System.out.println("Enter the size of the array that is to be created: "); int size = sc.nextInt(); int[] myArray ... Read More
In Java, serialization is a concept using which we can write the state of an object into a byte stream so that we can transfer it over the network (using technologies like JPA and RMI).To serialize an object −Make sure the class implements the Serializable interface.Create a FileOutputStream object representing the file (abstract path) of the file to which the object is to be stored.Create a ObjectOutputStream object by passing the above created FileOutputStream object.Write the object to the file using the writeObject() method.To de-serialize an objectCreate a FileInputStream object representing the file that contains the serialized object.Read the object ... Read More
If a single number is missing in an integer array that contains a sequence of numbers values, you can find it basing of the sum of numbers or, basing on the xor of the numbers.Based on the sum of the numbers −The sum of n sequential numbers will be [n*(n+1)]/2. Using this get the sum of the numbers the n numbers.Add all the elements in the array.Subtract the sum of the numbers in the array from the sum of the n numbers.Exampleimport java.util.Scanner; public class MissingNumber { public static void main(String[] args) { Scanner sc = ... Read More
To find the first non-repeating number in an array −Construct count array to store count of each element in the given array with same length and with initial value 0 for all elements.Compare each element in the array with all other elements, except itself.If match occurs increment its value in the count array.Get the index of the first 0 in the count array and print the element in the input array at this index.Exampleimport java.util.Arrays; public class NonRpeatingArray { public static void main(String args[]) { int array[] = {114, 225, 669, 996, 336, 6547, 669, 225, ... Read More
To find the first non-repeating number in an array −Construct count array to store count of each element in the given array with same length and with initial value 0 for all elements.Compare each element in the array with all other elements, except itself.If match occurs increment its value in the count array.Get the index of the first non-zero element in the count array and print the element in the input array at this index.Exampleimport java.util.Arrays; public class NonRpeatingArray { public static void main(String args[]) { int array[] = {114, 225, 669, 996, 336, 6547, 669, ... Read More
You can reverse a String in several ways, without using the reverse() function.Using recursion − Recursion is the process of repeating items in a self-similar way. In programming languages, if a program allows you to call a function inside the same function, then it is called a recursive call of the function. You can reverse a string using recursive function as shown in the following program.Exampleimport java.util.Scanner; public class StringReverse { public static String reverseString(String str){ if(str.isEmpty()){ return str; }else{ return reverseString(str.substring(1))+str.charAt(0); } ... Read More
The class named File of the java.io package represents a file or directory (path names) in the system. This class provides various methods to perform various operations on files/directories.The delete() method of the File class deletes the file/directory represented by the current File object.This ListFiles() method of the File class returns an array holding the objects (abstract paths) of all the files (and directories) in the path represented by the current (File) object.Therefore, to delete a folder along with its sub directories and files, you need to define a recursive method.ExampleFollowing Java program deletes the specified directory recursively −import java.io.File; ... Read More
He class named File of the java.io package represents a file or directory (path names) in the system. This class provides various methods to perform various operations on files/directories.The lastModified() method of the File class returns the last modified time of the file/directory represented by the current File object. You can get the last modified time of a particular file using this method.ExampleFollowing Java program gets the last modified time of a directory −import java.io.File; import java.util.Date; public class GettingLastmodifiedTime { public static void main(String args[]) { String filePath = "D://ExampleDirectory//"; //Creating the File ... Read More
The class named File of the java.io package represents a file or directory (path names) in the system. This class provides various methods to perform various operations on files/directories.The isHidden() method of the File class verifies weather the (abstract path of) file/directory represented by the current File object, is hidden.The ListFiles() method of the File class returns an array holding the objects (abstract paths) of all the files (and directories) in the path represented by the current (File) object.Therefore, to list all the hidden files in a directory get all the file objects using the ListFiles() method, verify weather each ... Read More