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Assignment 2 A Solution

Question 1 Write a program to create an ArrayList of Integer type and perform the below operation on it​

  1. Display the list
  2. Ask the user to enter a number and search that number is it present in the list or not.
  3. Remove an element from an asked position.
  4. Add a condition to check the ArrayList is empty or not.
import java.util.*;

public class Q1 {
    public static void main(String[] args) {
        ArrayList<Integer> numbers = new ArrayList<>();
        numbers.add(10);
        numbers.add(20);
        numbers.add(30);
        numbers.add(40);
        numbers.add(50);
        numbers.add(60);
        numbers.add(70);
        System.out.println(numbers);
        
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter number to be searched: ");
        int searchNumber = scanner.nextInt();
        System.out.println("The element " + searchNumber + " is present in the ArrayList: " + numbers.contains(searchNumber));
        
        System.out.print("Enter position of number to be removed: ");
        int position = scanner.nextInt();
        numbers.remove(position);
        System.out.println("After removal: " + numbers);
        
        boolean isEmpty = numbers.isEmpty();
        if (isEmpty) {
            System.out.println("The ArrayList is empty.");
        } else {
            System.out.println("The ArrayList is not empty.");
        }
        
        scanner.close();
    }
}

Credit:

Question 2 Create a class Student having member variable name, age, mark and required member variable. Create an LikedList of Student type and perform the below operation on it​

  1. Display the list
  2. Ask the user to enter a student object and print the existence of the object. Specify is the object is search according to reference or contain.
  3. Remove an specified student object.
  4. Count the number of object present in the list
import java.util.*;

class Student {
    String name;
    int age;
    double mark;

    Student(String name, int age, double mark) {
        this.name = name;
        this.age = age;
        this.mark = mark;
    }

    public boolean equals(Object obj) {
        if (obj instanceof Student) {
            Student other = (Student) obj;
            return this.name.equals(other.name) && this.age == other.age && this.mark == other.mark;
        }
        return false;
    }
}

public class Q2 {
    public static void main(String[] args) {
        LinkedList<Student> studentList = new LinkedList<>();

        studentList.add(new Student("Vivek", 19, 10.0));
        studentList.add(new Student("Aditi", 19, 10.0));
        studentList.add(new Student("Arya", 20, 10.0));

        System.out.println("Number of students now: " + studentList.size());

        for (Student student : studentList) {
            System.out.println(student.name + " " + student.age + " " + student.mark);
        }

        Student searchStudent = new Student("Aditi", 19, 10.0);

        System.out.println("Student exists in the list? " + studentList.contains(searchStudent));

        Student removeStudent = new Student("Arya", 20, 10.0);

        studentList.remove(removeStudent);

        System.out.println("Number of students now: " + studentList.size());
    }
}

Credit:

Question 3 Write a java program to convert a decimal to binary equivalent using stack(Stack collection)​

import java.util.*;

public class Q3 {
    public static void main(String[] args) {
        Stack<Integer> binaryStack = new Stack<Integer>();
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a Decimal Integer: ");
        int decimalNumber = sc.nextInt();

        while (decimalNumber > 0) {
            int remainder = decimalNumber % 2;
            binaryStack.push(remainder);
            decimalNumber /= 2;
        }

        System.out.print("The binary equivalent is: ");

        while (!binaryStack.isEmpty()) {
            System.out.print(binaryStack.pop());
        }

        sc.close();
    }
}

Credit:

Question 4 Write a java program to evaluate a postfix expression using Stack​

import java.util.*;

public class Q4 {
  
    public static int evaluatePostfix(String postfix) {
        Stack<Integer> stack = new Stack<Integer>();
        for (int i = 0; i < postfix.length(); i++) {
            char ch = postfix.charAt(i);
            if (Character.isDigit(ch)) {
                stack.push(ch - '0');
            } else {
                int operand2 = stack.pop();
                int operand1 = stack.pop();
                int result = 0;
                switch (ch) {
                    case '+':
                        result = operand1 + operand2;
                        break;
                    case '-':
                        result = operand1 - operand2;
                        break;
                    case '*':
                        result = operand1 * operand2;
                        break;
                    case '/':
                        result = operand1 / operand2;
                        break;
                }
                stack.push(result);
            }
        }
        return stack.pop();
    }

    public static void main(String args[]) {
        String postfix = "53+82-*";
        int result = evaluatePostfix(postfix);
        System.out.println("The result of " + postfix + " is " + result);
    }
}

Credit:

Question 5 Write a java program to traverse a graph using breadth first search (use ArrayDeque collection )​

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The answer has not yet been updated.

Question 6 Write a java program to traverse a graph using depth first search (use Stack collection )​

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The answer has not yet been updated.