My assignment is about a University database using LinkedList (Java). First, I w

Question

My assignment is about a University database using LinkedList (Java). First, I want to make two functions which are AddCollege and DeleteCollege.

Here are the details:

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You should create two classes, one for College and the other for Department.
A College should have at least the following parameters: (Please note that you may add additional parameters of your choice for each college if it helps you in any way)

College Name: string ( for example, Business, Engineering, etc.)
Number of departments: int (this will be the number of department within a college)
departments: Department (this field is of type Department reference/pointer which points to the object of type Department)
next: College (this reference/pointer will point to the next college in the list)

You should provide functions to support the following operations:

1. Add a new college in the list (take input from user, all the fields and add a new college)

2. Delete a college from the list (based on college’s name). Notice that deleting a college should delete all the departments of that college as well.

The head should be called PMU.

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Please help me figure out those two functions first and tell me where do I define the head, too... like in which class? department class or college class?

Explanation / Answer

package assignment;

import java.util.Scanner;

public class CollegeDeptLinkedListTest {

   public static void main(String[] args) {
       CollegeLinkedList cll = new CollegeLinkedList();
       cll.addCollege();
       cll.addCollege();
       cll.deleteCollege();
   }
  
  
}

class CollegeLinkedList {
  
   private College head;
  
   public CollegeLinkedList() {
       //this is dummy college for head
       head = new College("PMU",0,null);
   }
  
   public void addCollege() {
       Scanner sc = new Scanner(System.in);
       String name = null;
       String deptName = null;
       int noOfDepts = 0;
       Department depts = null;
       Department temp = null;
       System.out.println("Enter college name:");
       name = sc.nextLine();
       do {
           System.out.println("Enter no of departments:");
           noOfDepts = sc.nextInt();
       }while(noOfDepts <= 0);
      
       if(noOfDepts > 0) {
           for(int i = 1; i <= noOfDepts; i++ ) {
               System.out.println("Enter department#"+i+" name:");
               deptName = sc.nextLine();
               if(depts == null)
                   depts = new Department(deptName);
               else {
                   depts.setNext(new Department(deptName));
               }
           }
       }
      
       head.setNext(new College(name,noOfDepts, depts));
   }
  
   public void deleteCollege() {
       Scanner sc = new Scanner(System.in);
       String collegeName = null;
       College cur = head.getNext();
       College prev = head;
      
       System.out.println("Enter college name to delete:");
       collegeName = sc.nextLine();
      
       boolean found = false;
       while(cur != null) {
           if(cur.getName().equals(collegeName)) {
               prev.setNext(cur.getNext());
               found = true;
               break;
           }
           prev = cur;
           cur = cur.getNext();
       }
       if(!found)
           System.out.println(" College : "+collegeName +" not found");
   }
}

class College {
   private String name;
   private int noOfDepartments;
   private Department departments;
   private College next;
  
   public College(String name,int noOfDepartments, Department departments ) {
       this.name = name;
       this.noOfDepartments = noOfDepartments;
       this.departments = departments;
       next = null;
   }
  
   public String getName() {
       return name;
   }
   public void setName(String name) {
       this.name = name;
   }
   public int getNoOfDepartments() {
       return noOfDepartments;
   }
   public void setNoOfDepartments(int noOfDepartments) {
       this.noOfDepartments = noOfDepartments;
   }
   public Department getDepartments() {
       return departments;
   }
   public void setDepartments(Department departments) {
       this.departments = departments;
   }
   public College getNext() {
       return next;
   }
   public void setNext(College next) {
       this.next = next;
   }
  
  
}

class Department {
   private String name;
   private Department next;
  
  
   public Department(String name ) {
       this.name = name;
       next = null;
   }
   public String getName() {
       return name;
   }
   public void setName(String name) {
       this.name = name;
   }
   public Department getNext() {
       return next;
   }
   public void setNext(Department next) {
       this.next = next;
   }
  
  
}

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