Assignment 1: Collections
Set A
a) Write a java program to accept names of ‘n’ cities, insert same into array list collection and display the contents of same array list, also remove all these elements.
import java.util.*;
public class A1 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
ArrayList<Object> al = new ArrayList<>();
System.out.println("Enter How many cities :");
int n = sc.nextInt();
System.out.println("Enter the Cities :");
sc.nextLine();
for (int i = 0; i < n; i++) {
String c = sc.nextLine();
al.add(c);
}
System.out.println("Cities :" + al);
System.out.println("ArrayList after removing the elements :");
al.clear();
sc.close();
}
}
b) Write a java program to read ‘n’ names of your friends, store it into linked list, also display contents of the same.
import java.util.*;
public class A2 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
LinkedList<Object> ll = new LinkedList<>();
System.out.println("Enter How many Friends :");
int n = sc.nextInt();
System.out.println("Enter the "+n+" Friends :");
sc.nextLine();
for (int i = 0; i < n; i++) {
String fl = sc.nextLine();
ll.add(fl);
}
System.out.println("Friends :" + ll);
sc.close();
}
}
c) Write a program to create a new tree set, add some colors (string) and print out the tree set.
import java.util.Scanner;
import java.util.TreeSet;
public class A3 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
TreeSet<Object> ts = new TreeSet<>();
System.out.println("Enter How many Colours :");
int n = sc.nextInt();
System.out.println("Enter the "+n+" Colours :");
sc.nextLine();
for (int i = 0; i < n; i++) {
String c = sc.nextLine();
ts.add(c);
}
System.out.println("Colours :" + ts);
sc.close();
}
}
d) Create the hash table that will maintain the mobile number and student name. Display the contact list.
import java.util.Hashtable;
public class A4 {
public static void main(String[] args) {
Hashtable<String, String> hashtable = new Hashtable<String, String>();
hashtable.put("Prasad", "8796465800");
hashtable.put("Ashish", "8806503414");
hashtable.put("Suhas", "8629913414");
hashtable.put("Sanket", "7118919895");
System.out.println(hashtable);
}
}
Set B
a) Accept ‘n’ integers from the user. Store and display integers in sorted order having proper collection class. The collection should not accept duplicate elements.
import java.util.TreeSet;
import java.util.Scanner;
public class B1 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
TreeSet<Object> ts = new TreeSet<>();
System.out.println("Enter how many Numbers: ");
int n = sc.nextInt();
System.out.println("Enter the " + n + " Numbers: ");
for (int i = 0; i < n; i++) {
int num = sc.nextInt();
ts.add(num);
}
System.out.println("Numbers in Sorted Order and without Duplication :" + ts);
sc.close();
}
}
b) Write a program to sort HashMap by keys and display the details before sorting and after sorting.
import java.util.HashMap;
import java.util.TreeMap;
public class B2 {
public static void main(String[] args) {
HashMap<String, Integer> map = new HashMap<>();
map.put("Prasad", 2002);
map.put("Ashish", 2001);
map.put("Suhas", 2002);
map.put("Swayam", 2001);
map.put("Sanket", 2002);
System.out.println("\nHashMap Details Before Sorting :\n" + map);
TreeMap<Object,Object> tm = new TreeMap<>(map);
System.out.println("\nHashMap Details After Sorting :\n" + tm);
}
}
c) Write a program that loads names and phone numbers from a text file where the data is organized as one line per record and each field in a record are separated by a tab (\t).it takes a name or phone number as input and prints the corresponding other value from the hash table (hint: use hash tables)
import java.io.*;
import java.util.Hashtable;
import java.util.Scanner;
public class B3 {
public static void main(String[] args) {
try {
File f = new File("B3.txt");
BufferedReader br = null;
br = new BufferedReader(new FileReader(f));
Hashtable<String, String> table = new Hashtable<>();
Scanner sc = new Scanner(System.in);
String line = "";
while ((line = br.readLine()) != null) {
String[] parts = line.split(":");
String name = parts[0].trim();
String number = parts[1].trim();
if (!name.equals("") && !number.equals("")) {
table.put(name, number);
}
}
System.out.println("Enter Name :");
String key = sc.nextLine();
if (table.containsKey(key)) {
System.out.println(table.get(key));
br.close();
sc.close();
}
} catch (Exception e) {
System.out.println(e);
}
}
}
Set C
a) Create a java application to store city names and their STD codes using an appropriate collection. The GUI should allow the following operations:
i. Add a new city and its code (No duplicates)
ii. Remove a city from the collection
iii. Search for a city name and display the code
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class C1 extends JFrame implements ActionListener {
JTextField txtname, txtstd;
JButton btnadd, btndelete, btnsearch;
JPanel p1;
Hashtable<String, String> table = new Hashtable<>();
C1() {
setTitle("City STD Code Information");
setSize(700, 500);
setVisible(true);
setLayout(new GridLayout(3, 2, 20, 20));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel name = new JLabel("Enter City Name: ");
add(name);
txtname = new JTextField(10);
add(txtname);
JLabel stdcode = new JLabel("Enter STD Code: ");
add(stdcode);
txtstd = new JTextField(10);
add(txtstd);
JLabel op = new JLabel("Choose Operation: ");
add(op);
p1 = new JPanel();
p1.setLayout(new GridLayout(1, 3, 5, 5));
btnadd = new JButton("Add");
p1.add(btnadd);
btnadd.addActionListener(this);
btndelete = new JButton("Delete");
p1.add(btndelete);
btndelete.addActionListener(this);
btnsearch = new JButton("Search");
p1.add(btnsearch);
btnsearch.addActionListener(this);
add(p1);
}// SETC1
public void actionPerformed(ActionEvent ae) {
String name = (txtname.getText());
String std = (txtstd.getText());
if (ae.getSource() == btnadd) {
// System.out.println(table.containsKey(name) || table.containsValue(std));
if (table.containsKey(name) || table.containsValue(std)) {
String s2 = "Duplicates are not allowded ";
JOptionPane.showMessageDialog(null,s2,s2, JOptionPane.ERROR_MESSAGE);
} else {
table.put(name, std);
System.out.println(table);
JOptionPane.showMessageDialog(null, "Succesfully Added City & STD Code", name,
JOptionPane.INFORMATION_MESSAGE);
}
txtname.setText("");
txtstd.setText("");
}
if (ae.getSource() == btndelete) {
String s1 = JOptionPane.showInputDialog(null, "Enter City to remove");
table.remove(s1);
JOptionPane.showMessageDialog(null, "Succesfully removed City & STD Code", name,
JOptionPane.INFORMATION_MESSAGE);
}
if (ae.getSource() == btnsearch) {
String s1 = JOptionPane.showInputDialog(null, "Enter City");
if (table.containsKey(s1)) {
String s2 = "STD Code: " + table.get(s1);
JOptionPane.showMessageDialog(null, s2);
} else {
JOptionPane.showMessageDialog(null, "ERROR OCCURED");
}
}
}
public static void main(String[] args) {
new C1();
}
}
b) Write a program to create link list of integer objects. Do the following:
i. add element at first position
ii. delete last element
iii. display the size of link list
import java.util.LinkedList;
import java.util.Scanner;
public class C2 {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
LinkedList<Object> ll = new LinkedList<>();
ll.add(1);
ll.add(2);
ll.add(3);
System.out.println("\nElements in List :\n" + ll);
ll.addFirst(0);
System.out.println("\nList after adding Elements at First :\n" + ll);
ll.removeLast();
System.out.println("\nList after deleting Last Element :\n" + ll);
System.out.println("\nSize of the List :\n" + ll.size());
sc.close();
}
}
c) Read a text file, specified by the first command line argument, into a list. The program should then display a menu which performs the following operations on the list:
1. Insert line
2. Delete line
3. Append line
4. Modify line
5. Exit When the user selects Exit,
save the contents of the list to the file and end the program.
import java.util.*;
import java.io.*;
public class C3 {
public static void main(String arg[]) {
Scanner sc = new Scanner(System.in);
try {
// Here, we have used command line argument , so at the time of run the code use command java C3 C3.txt
File f = new File(arg[0]);
BufferedReader br = null;
br = new BufferedReader(new FileReader(f));
FileOutputStream fout = new FileOutputStream(arg[0]);
int ch;
ArrayList<Object> al = new ArrayList<>();
String line = "";
while ((line = br.readLine()) != null) {
al.add(line);
} // while
// main logic
do {
System.out.println("1.Insert Line\n2.Delete Line\n3.Append Line\n4.Modify Line\n5.Exit");
System.out.println("Enter choice: ");
ch = sc.nextInt();
String l1 = "This is a new Line";
switch (ch) {
case 1:
al.add(l1);
break;
case 2:
al.remove(l1);
break;
case 3:
al.add(l1);
break;
case 4:
int n = al.size() - 1;
al.set(n, "\tUpdated line");
break;
case 5:
ListIterator<Object> li = al.listIterator();
while (li.hasNext()) {
String l2 = (String) li.next();
byte b[] = l2.getBytes();
fout.write(b);
}
System.exit(1);
break;
}
} while (ch < 6);
br.close();
fout.close();
} catch (Exception e) {
System.out.println(e);
}
sc.close();
}
}
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