Question

plz use doubly linked list. java

Q1) Create a program that do the following:

1. Asks the user to enter n marks for n students, read the marks and the names and store them in a double linked list.

2. Write a method to find the largest mark and print the name of the student having that mark

3. Write a method to print the content of the list (name, mark)

4. Write a method to search the list for a given mark and prints the result

6. Insert 2 new students to the list (print the list before and after the insertion)

7. Delete any students with the first letter "D" in his name, (print the list before and after the deletion)

Submit .java files only.

Answer 1

package learning;
import java.util.*;

class Student{
        public String name;
        public int marks;
        
        Student(String name,int marks){
                this.name = name;
                this.marks = marks;
        }
}

class node{
        public Student S;
        node next;
        node prev;
        
        node(Student S){
                this.S = S;
                next=null;
                prev=null;
        }
}

class DLL{
        node head=null;
        node tail=null;
        
        void insert(String name,int marks) {
                if(head == null) {
                        head = new node(new Student(name,marks));
                        tail = head;
                }else {
                        tail.next =  new node(new Student(name,marks));
                        
                        tail.next.prev = tail;
                        
                        tail = tail.next;
                        
                }
        }

        void largest() {
                node temp = head;
                Student Max = new Student("dummy",-1000);
                while(temp!=null) {
                        if(temp.S.marks > Max.marks) {
                                Max = temp.S;
                        }
                        
                        temp = temp.next;
                }
                System.out.println("Student with Largest Marks: ");
                System.out.println(Max.name);
                System.out.println(Max.marks);
                System.out.println();
        }
        
        void printList() {
                node temp = head;
        
                while(temp!=null) {
                        System.out.println(temp.S.name);
                        System.out.println(temp.S.marks);
                        temp = temp.next;
                }
        }
        
        void printMarks(int m) {
                node temp = head;
                
                while(temp!=null) {
                        
                        if(temp.S.marks == m) {
                                System.out.println(temp.S.name);
                                System.out.println(temp.S.marks);
                                System.out.println();
                        }
                        
                        temp = temp.next;
                }
        }
        
        void delete(char c) {
                node temp = head;
                
                while(temp!=null) {
                        
                        if(temp.S.name.charAt(0) == c) {
                                temp.prev.next = temp.next;
                                temp.next.prev = temp.prev;
                        }
                        
                        temp = temp.next;
                }
        }
        
        
}

class Main {
        public static void main(String[] args) {
                        
                        Scanner input = new Scanner(System.in);
                        DLL D = new DLL();
                        
                        System.out.print("Enter the number of students to insert:");

                        int n = Integer.parseInt(input.nextLine());
                        
                        for(int i=0;i<n;++i) {
                                System.out.print("Enter the name of the student:");
                                String name = input.nextLine();
                                System.out.print("Enter the marks of the student:");
                                int marks = Integer.parseInt(input.nextLine());
                                D.insert(name, marks);
                                
                        }
                        System.out.println();
                        
                        
                        
                        D.printList();
                        
                        System.out.println();
                        
                        System.out.print("Enter the marks to search for:");
                        int marks = Integer.parseInt(input.nextLine());
                        
                        D.printMarks(marks);
                        
                        System.out.println();
                        
                        D.largest();
                        
                        System.out.print("Enter the first Character of student name to delete:");
                        
                        char c =input.nextLine().charAt(0);
                        
                        D.delete(c);
                        
                        System.out.print("List after deleting students with first character "+ c + ":\n");
                        
                        D.printList();
                        
        }
}
        

OUTPUT: