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Java Java Objects Delivering the MVP Forum

Cant solve the 4th puzzle please help

Cant solve the 4th puzzle please help

Forum.java
public class Forum {
  private String topic;

 public Forun(String topic){

  this.topic = topic;

 }

  public String getTopic() {
    return topic;
  }



  public void addPost(ForumPost post) {
    System.out.printf("A new post in %s topic from %s %s about %s is available",
            topic,
            post.getAuthor().getFirstName(),
            post.getAuthor().getLastName(),
            post.getTitle()
    );
  }


}
User.java
public class User {

  private String firstName = "";
  private String lastName = "";

  public User(String firstName, String lastName) {

    this.firstName = firstName;
    this.lastName = lastName;

  }

 public String getFirstName(){

 return firstName;

 }


  public String getLastName(){

  return lastName;

  }
}
ForumPost.java
public class ForumPost {
  private User author;
  private String title;
  private String description;

  // TODO: add a constructor that accepts the author, title and description
  public ForumPost(User author, String title, String description) {
    this.author = author;
    this.title = title;
    this.description = description;
  }


  public User getAuthor() {
    return author;
  }

  public String getTitle() {
    return title;
  }

  public String getDescription() {
    return description;
  }
}
Main.java
public class Main {

  public static void main(String[] args) {
    System.out.println("Beginning forum example");
    if (args.length < 2) {
      System.out.println("Usage: java Main <first name> <last name>");
      System.err.println("<first name> and <last name> are required");
      System.exit(1);
    }

    Forum forum = new Forum("Java");
    ForumPost.getFirstName();
    ForumPost.getLastName();
    // TODO: pass in the first name and last name that are in the args parameter
    User author = new User();
    ForumPost.User getAuthor(); 
    ForumPost.getTitle();
    ForumPost.getDescription();
    // TODO: initialize the forum post with the user created above and a title and description of your choice
    ForumPost post = new ForumPost();
    forum.addPost(post);


  }

}

3 Answers

Manish Giri
Manish Giri
16,266 Points

Look at the first comment -

// TODO: pass in the first name and last name that are in the args parameter

If you're not clear on the args parameter yet, when you compile and execute your Java program, you can also pass in some commands at this time. These (String) commands get saved in an array conventionally called args, and it is this String array that's passed into the parameter of the main() method, as shown below -

public static void main(String[] args) {

So, if you compiled your code with the commands Hello World (either from the terminal or from IDE), this would be the value of the args array - ["Hello", "World"].

So, args[0] would be the string "Hello", args[1] would be the string "World".

This is what is being referred to in the comment -

pass in the first name and last name that are in the args parameter

What you need to do is, get the firstName and lastName values by using the args array. Then use these two values to construct the User object -

// TODO: initialize the forum post with the user created above

Once you have the User object, you can then use it to construct the ForumPost object, which is the last part of the task.

Hope this helps.

I did'n get it what is User author.Is User a datatype

Manish Giri
Manish Giri
16,266 Points

Look at the 2nd line of the ForumPost class - private User author.

author is the name of the variable representing the User object.

Can some one explain the last puzzle again,I did'n understand it