I am neo java week 12

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Skill builder

1. Using Java Library ArrayList as a List Interface implementation, input N integers from standard input and add to the list only if they form an increasing sequence.

import java.util.*; import java.lang.*; import java.io.*; class Q01Simple_List { public static void main (String[] args) throws java.lang.Exception { Scanner input = new Scanner(System. in); // Inputnumber of elements int number_of_elements = input. nextInt(); if (number_of_elements <= 0) return; ArrayList<Integer> numList = new ArrayList<Integer>(); for (int ctr = 0; ctr < number_of_elements; ctr++) { // Input next element int num = input. nextInt(); ListIterator<Integer> listIter = numList.listIterator(numList.size()); if (listIter.hasPrevious()) { if( listIter.previous() < num) numList.add(num); } else numList.add(num); } System.out.println(numList); } }

2. sort() a List of Objects

import java.io.*; import java.util.*; class Hall implements Comparable<Hall> { public Hall(String name, String contactNumber, double costPerDay, String ownerName) { this.name = name; this.contactNumber = contactNumber; this.costPerDay = costPerDay; this.ownerName = ownerName; } public Hall() { this.name = null; this.contactNumber = null; this.costPerDay = 0; this.ownerName = null; } private String name; private String contactNumber; private double costPerDay; private String ownerName; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getContactNumber() { return contactNumber; } public void setContactNumber(String contactNumber) { this.contactNumber = contactNumber; } public double getCostPerDay() { return costPerDay; } public void setCostPerDay(double costPerDay) { this.costPerDay = costPerDay; } public String getOwnerName() { return ownerName; } public void setOwnerName(String ownerName) { this.ownerName = ownerName; } @Override public int compareTo(Hall h) { return Double.compare(this.costPerDay,h.costPerDay ); } public String toString() { return name+" "+contactNumber+" "+costPerDay+" "+ownerName; } } class Main { public static void main(String [] args) { int i,n; Scanner sc = new Scanner(System.in); n = Integer.parseInt(sc.nextLine()); Hall [] h = new Hall[n]; ArrayList<Hall> halls = new ArrayList<Hall>(n); for(i=0;i<n;i++) { h[i] = new Hall(); h[i].setName(sc.nextLine()); h[i].setContactNumber(sc.nextLine()); h[i].setCostPerDay(Double.parseDouble(sc.nextLine())); h[i].setOwnerName(sc.nextLine()); halls.add(h[i]); } Collections.sort(halls); for(i=0;i<n;i++) { System.out.println(halls.get(i)); } } }

3. Create a class ItemType with the following attributes.

import java.util.ArrayList; import java.util.Iterator; import java.util.List; import java.util.Scanner; class ItemType{ private String name; private Double deposit; private Double costPerDay; @Override public String toString() { return String.format( "%-20s%-20s%-20s",name,deposit,costPerDay); } public ItemType(String name, Double deposit, Double costPerDay) { super(); this.name = name; this.deposit = deposit; this.costPerDay = costPerDay; } } class ArrayListObjectMain { public static void main(String args[]) { List <ItemType> items = new ArrayList<>(); Scanner sc = new Scanner(System.in); int n = Integer.parseInt(sc.nextLine()); for(int i=0;i<n;i++) { String name = sc.nextLine(); Double deposit = Double.parseDouble(sc.nextLine()); Double costPerDay = Double.parseDouble(sc.nextLine()); items.add(new ItemType(name,deposit,costPerDay)); } Iterator it = items.iterator(); System.out.format("%-20s%-20s%-20s","Name","Deposit","Cost Per Day"); System.out.println(); while(it.hasNext()) { System.out.println(it.next()); } } }

4. Using Java Library ArrayList as a List implementation, input N integers from standard input and store sequentially in the List. In place, reverse the list by swapping the elements from the ends inwards and print the list after each swap.

import java.util.*; import java.lang.*; import java.io.*; class Q02Medium_List { public static void main (String[] args) throws java.lang.Exception { Scanner input = new Scanner(System. in); // Input number of elements int number_of_elements = input. nextInt(); if (number_of_elements <= 0) return; ArrayList<Integer> numList = new ArrayList<Integer>(); for (int ctr = 0; ctr < number_of_elements; ctr++) { // Input next element int num = input. nextInt(); numList.add(num); } ListIterator<Integer> begin = numList.listIterator(0); ListIterator<Integer> end = numList.listIterator(numList.size()); for (int i = 0; i < numList.size()/ 2; i++) { int tmp = begin.next(); begin.set(end.previous()); end.set(tmp); System.out.println(numList); } } }

5. Input a string with possibly repeated words separated by spaces

import java.util.*; import java.lang.*; import java.io.*; class Q01Medium_Set { public static void main (String[] args) throws java.lang.Exception { Scanner input = new Scanner(System. in); String line = input.nextLine(); String words[] = line.split("[\\s]+"); Set<String> strings = new HashSet<String>(); for (String word: words) { strings.add(word); } System.out.println(strings.size()); } }

6. Vault Services company has to organize the employee details based on their salary

import java.io.*; import java.util.*; import java.util.Comparator; import java.util.TreeSet; class Empl{ private String name; private int salary; public Empl(String n, int s){ this.name = n; this.salary = s; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getSalary() { return salary; } public void setSalary(int salary) { this.salary = salary; } public Empl(){ this.name = null; this.salary = 0; } public String toString(){ return this.name+"-"+this.salary; } } class Main { public static void main(String a[]){ int i,n; Scanner sc = new Scanner(System.in); n = Integer.parseInt(sc.nextLine()); TreeSet<Empl> nameComp = new TreeSet<Empl>(new MyNameComp()); Empl[] em = new Empl[n]; for(i=0;i<n;i++) { em[i] = new Empl(); em[i].setName(sc.nextLine()); em[i].setSalary(Integer.parseInt(sc.nextLine())); nameComp.add(em[i]); } System.out.println("After sorting the employee names:"); for(Empl e:nameComp){ System.out.println(e); } System.out.println("After sorting the salary:"); TreeSet<Empl> salComp = new TreeSet<Empl>(new MySalaryComp()); for(i=0;i<n;i++) { salComp.add(em[i]); } for(Empl e:salComp){ System.out.println(e); } } } class MyNameComp implements Comparator<Empl>{ @Override public int compare(Empl e1, Empl e2) { return e1.getName().compareTo(e2.getName()); } } class MySalaryComp implements Comparator<Empl>{ @Override public int compare(Empl e1, Empl e2) { if(e1.getSalary() > e2.getSalary()){ return 1; } else { return -1; } } }

7. Write a program to check if an element exists in the HashSet.

import java.io.*; import java.util.*; class Main { public static void main(String[] args) { int i,n; Scanner sc = new Scanner(System.in); n = Integer.parseInt(sc.nextLine()); Set<String> hs = new HashSet<>(n); for(i=0;i<n;i++) { hs.add(sc.nextLine()); } String hsName = sc.nextLine(); if(hs.contains(hsName)) { System.out.println(hsName + " is in the hash set."); } else { System.out.println(hsName + " is not in the hash set."); } } }

8. Use remove() and isEmpty() methods of the ArrayList API and implement them in our application

import java.io.*; import java.util.*; class Hall { private String name; private String contactNumber; private double costPerDay; private String ownerName; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getContactNumber() { return contactNumber; } public void setContactNumber(String contactNumber) { this.contactNumber = contactNumber; } public double getCostPerDay() { return costPerDay; } public void setCostPerDay(double costPerDay) { this.costPerDay = costPerDay; } public String getOwnerName() { return ownerName; } public void setOwnerName(String ownerName) { this.ownerName = ownerName; } public Hall() { this.name = null; this.contactNumber = null; this.costPerDay =0; this.ownerName = null; } public Hall(String name, String contactNumber, Double costPerDay,String ownerName) { this.name = name; this.contactNumber = contactNumber; this.costPerDay = costPerDay; this.ownerName = ownerName; } public void display() { System.out.printf("%-20s%-20s%-20s%-20s\n",name,contactNumber,costPerDay,ownerName); } } class Main { public static void main(String [] args) { int i,n; Scanner sc = new Scanner(System.in); n = Integer.parseInt(sc.nextLine()); ArrayList<Hall> h1 = new ArrayList<>(n); Hall [] h = new Hall[n]; for(i=0;i<n;i++) { h[i] = new Hall(); h[i].setName(sc.nextLine()); h[i].setContactNumber(sc.nextLine()); h[i].setCostPerDay(Double.parseDouble(sc.nextLine())); h[i].setOwnerName(sc.nextLine()); h1.add(h[i]); } int index = Integer.parseInt(sc.nextLine()); if(h1.isEmpty()) { System.out.println("The list is empty"); } else { h1.remove(index); System.out.printf("%-20s%-20s%-20s%-20s\n","Name","Contact Number","CostperDay","Owner Name"); } for(i=0;i<n-1;i++) { h1.get(i).display(); } } }

Challange yourself

1. Input a positive integer N (N > 0), input N strings, and sort the strings in place in the order of increasing length

import java.util.*; import java.lang.*; import java.io.*; class Q01Simple_Sort { public static void main (String[] args) throws java.lang.Exception { Scanner input = new Scanner(System. in); // Input number of elements int number_of_elements = input. nextInt(); input. nextLine(); if (number_of_elements <= 0) return; List<String> list = new ArrayList<>(); for (int ctr = 0; ctr < number_of_elements; ctr++) { // Input next string String str = input. nextLine(); list.add(str); } Collections.sort(list, new Comparator<String>() { public int compare(String o1, String o2) { return o1.length() - o2.length(); }}); System.out.println(list); } }

2. Manipulation in ArrayList

import java.io.*; import java.util.*; class Hall { private String name; private String contactNumber; private Double costPerDay; private String ownerName; public String getName() { return name; } public void setName(String name) { this.name = name; } public String getContactNumber() { return contactNumber; } public void setContactNumber(String contactNumber) { this.contactNumber = contactNumber; } public Double getCostPerDay() { return costPerDay; } public void setCostPerDay(Double costPerDay) { this.costPerDay = costPerDay; } public String getOwnerName() { return ownerName; } public void setOwnerName(String ownerName) { this.ownerName = ownerName; } public Hall() { this.name = null; this.contactNumber = null; this.costPerDay = (double) 0; this.ownerName = null; } public Hall(String name, String contactNumber, Double costPerDay, String ownerName) { this.name = name; this.contactNumber = contactNumber; this.costPerDay = costPerDay; this.ownerName = ownerName; } } class HallBO { public List<Hall> getHallList(){ int i,n; Scanner sc = new Scanner(System.in); n = Integer.parseInt(sc.nextLine()); Hall[] h = new Hall[n]; ArrayList<Hall> ha = new ArrayList<Hall>(n); for(i=0;i<n;i++){ h[i] = new Hall(); h[i].setName(sc.nextLine()); h[i].setContactNumber(sc.nextLine()); h[i].setCostPerDay(Double.parseDouble(sc.nextLine())); h[i].setOwnerName(sc.nextLine()); ha.add(h[i]); } return ha; } public void display(List<Hall> ha) { System.out.printf("%-20s%-20s%-20s%-20s\n","Name","Contact Number","Cost per Day","Owner Name") ; for(int i = 0;i < ha.size() ;i++) { System.out.format("%-20s%-20s%-20s%-20s\n",ha.get(i).getName(),ha.get(i).getContactNumber(),ha.get(i).getCostPerDay(),ha.get(i).getOwnerName()); } } } class Main { public static void main(String[] args) { List<Hall> ha = new ArrayList<Hall>(); HallBO hbo = new HallBO(); Scanner sc = new Scanner(System.in); ha = hbo.getHallList(); hbo.display(ha); } }

3. contains() & indexOf() methods in ArrayList

import java.io.*; import java.util.*; class Main { public static void main(String [] args) { int i,n; Scanner sc = new Scanner(System.in); n = Integer.parseInt(sc.nextLine()); ArrayList<String> hall = new ArrayList<>(n); for(i=0;i<n;i++) { hall.add(sc.nextLine()); } String search = sc.nextLine(); if(hall.contains(search)) { System.out.println(hall.indexOf(search)); } else { System.out.println(search+" hall is not found"); } } }