Creating a code in which Marks A social networking website hires you to meet the following requirements

Step-by-step explanation

Explanation:

import java.io.*;

public class Profile
{
        private String name;
        private String emailId;
        private String city;
        private String country;
        private Profile friendlist[];
        private Profile pendingRequests[];
        private int friendCount;
        private int pendingCount;

        private static final int MAX = 1000;
        
        public void createProfile(String name, String emailId, String city, String country)
        {
                this.name = name;
                this.emailId = emailId;
                this.city = city;
                this.country = country;
                this.friendlist=new Profile[MAX];
                this.pendingRequests = new Profile[MAX];
                this.friendCount=0;
                this.pendingCount=0;
        }

        public void addFriends(Profile profile)
        {
                profile.receiveFriendRequest(this, null);
        }

        public void addFriends(Profile profile, String message)
        {
                profile.receiveFriendRequest(this, message);
        }

        public void receiveFriendRequest(Profile profile, String message)
        {
                this.pendingRequests[this.pendingCount++] = profile;
        }

        public Profile[] getPendingRequests()
        {
                return this.pendingRequests;
        }

        public void acceptFriendRequest(Profile profile)
        {
                int index = this.pendingRequests.length;
                for(int i=0; i<this.pendingCount; i++)
                {
                        if(profile.equals(this.pendingRequests[i]))
                        {
                                index = i;
                        }
                }

                profile.addToFriendList(this);
                addToFriendList(profile);
                for(int i=index; i<this.pendingRequests.length-1; i++) this.pendingRequests[i] = this.pendingRequests[i+1];
                this.pendingRequests[this.pendingRequests.length-1]=null;
                this.pendingCount--;
        }

        private void addToFriendList(Profile profile)
        {
                this.friendlist[this.friendCount++] = profile;
        }

        public void removeFriend(Profile profile)
        {
                int index=this.friendlist.length;
                for(int i=0; i<this.friendlist.length; i++)
                {
                        if(this.friendlist[i] == null) break;
                        if(profile.equals(this.friendlist[i]))
                        {
                                index = i;
                        }
                }

                for(int i=index; i<this.friendlist.length-1; i++) this.friendlist[i] = this.friendlist[i+1];
                this.friendlist[this.friendlist.length-1] = null;
                this.friendCount--;
                profile.removeFriend(this);             
        }

        public void showFriends()
        {
                for(int i=0; i<this.friendlist.length; i++)
                {
                        if(this.friendlist[i] == null) break;
                        System.out.println(this.friendlist[i]);
                }
        }

        @Override
        public String toString()
        {
                return "Name: " + this.name + "\nEmail: " + this.emailId + "\nCity: " + this.city + "\nCountry: " + this.country;
        }

        @Override
        public boolean equals(Object obj)
        {
                if(obj == null) return false;
                if(!(obj instanceof Profile)) return false;
                Profile profile = (Profile)obj;
                if(this == profile) return true;                
                return(profile.name.equals(this.name) && profile.emailId.equals(this.emailId) && profile.city.equals(this.city) && profile.country.equals(this.country));
        }

        public boolean search(Profile profile)
        {
                for(int i=0; i<this.friendlist.length; i++)
                {
                        if(this.friendlist[i] == null) break;
                        if(profile.equals(this.friendlist[i])) return true;
                }
                return false;
        }

        public Profile[] checkMutualFriends(Profile profile)
        {
                int count = 0;
                for(int i=0; i<this.friendlist.length; i++)
                {
                        if(this.friendlist[i] == null) break;
                        if(profile.search(this.friendlist[i])) count++;
                }

                Profile mutual[] = new Profile[count];
                int k = -1;
                for(int i=0; i<this.friendlist.length; i++)
                {
                        if(this.friendlist[i] == null) break;
                        if(profile.search(this.friendlist[i])) mutual[++k] = this.friendlist[i];
                }
                return mutual;
        }
}

class ProfileTest
{
        private static final int MAX = 1000;

        public static void main(String args[]) throws IOException
        {
                BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
                Profile profiles[] = new Profile[MAX];
                int counter=0;

                while(true)
                {
                        System.out.print("\nMENU\n----\n1. Create new profile\n2. View Profiles\n3. Send friend request\n4. Accept requests\n5. View Friend List\n6. View mutual friends\n7. Exit\n\nEnter choice: ");
                        int choice = Integer.parseInt(br.readLine());

                        switch(choice)
                        {
                                case 1:
                                        System.out.print("CREATE PROFILE\n-----------------\nName: ");
                                        String name = br.readLine();
                                        System.out.print("Email: ");
                                        String email = br.readLine();
                                        System.out.print("City: ");
                                        String city = br.readLine();
                                        System.out.print("Country: ");
                                        String country = br.readLine();
                                        profiles[counter] = new Profile();
                                        profiles[counter++].createProfile(name, email, city, country);
                                        System.out.println("Profile successfully created!");
                                        break;

                                case 2:
                                        System.out.println("VIEW PROFILES\n--------------");
                                        for(int i=0; i<counter; i++)
                                        {
                                                System.out.println("ID: " + (i+1));
                                                System.out.println(profiles[i]);
                                        }
                                        break;

                                case 3:
                                        System.out.println("SEND FRIEND REQUEST\n--------------");
                                        System.out.print("Sender Profile ID: ");
                                        int senderID = Integer.parseInt(br.readLine()) - 1;
                                        System.out.print("Receiver Profile ID: ");
                                        int receiverID = Integer.parseInt(br.readLine()) - 1;
                                        if(senderID < 0 || senderID >= counter || receiverID < 0 || receiverID >= counter)
                                        {
                                                System.out.println("Invalid IDs");
                                        } else {
                                                System.out.print("Enter personalized message: ");
                                                String msg = br.readLine();
                                                profiles[senderID].addFriends(profiles[receiverID], msg);
                                                System.out.println("Friend request sent");
                                        }
                                        break;

                                case 4:
                                        System.out.print("Enter profile ID: ");
                                        int pid = Integer.parseInt(br.readLine()) - 1;
                                        System.out.println("PENDING REQUESTS\n--------------");
                                        Profile pending[] = profiles[pid].getPendingRequests();
                                        for(int i=0; i<pending.length; i++)
                                        {
                                                if(pending[i]==null) break;
                                                System.out.println(pending[i]);
                                                System.out.print("ACCEPT (Y/N) ? ");
                                                char x = br.readLine().trim().toUpperCase().charAt(0);
                                                if(x=='Y') profiles[pid].acceptFriendRequest(pending[i]);
                                        }
                                        break;

                                case 5:
                                        System.out.print("Enter profile ID: ");
                                        int pidf = Integer.parseInt(br.readLine()) - 1;
                                        System.out.println("FRIEND LIST\n--------------");
                                        profiles[pidf].showFriends();
                                        break;

                                case 6:
                                        System.out.print("Enter profile ID 1: ");
                                        int pid1 = Integer.parseInt(br.readLine()) - 1;
                                        System.out.print("Enter profile ID 2: ");
                                        int pid2 = Integer.parseInt(br.readLine()) - 1;
                                        Profile mutual[] = profiles[pid1].checkMutualFriends(profiles[pid2]);
                                        System.out.println("MUTUAL FRIENDS\n--------------");
                                        for(Profile p:mutual) System.out.println(p);
                                        break;

                                case 7:
                                        return;

                                default:
                                        System.out.println("Invalid choice");
                        }
                }
        }
}