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Java Java Objects Delivering the MVP Forum

Jiho Song
Jiho Song
16,469 Points

Why it is wrong? Java I

where to fix????

Forum.java
public class Forum {
  private String topic;

  // TODO: add a constructor that accepts a topic and sets the private field topic
 private Forum(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 {
  // TODO: add private fields for firstName and lastName
private String firstName;
private String lastName;

  private User(String firstName, String lastName) {
    // TODO: set and add the private fields
this.firstName=firstName;
    this.lastName=lastName;
  }
public String getFirstName(){
  return firstName;
}

public String getLastName(){
  return lastName;
}
  // TODO: add getters for firstName and lastName

}
ForumPost.java
public class ForumPost {
  private User author;
  private String title;
  private String description;
private ForumPost(User author, String title, String description){
  this.author = author;
  this.title = title;
    this.description = description;
}
  // TODO: add a constructor that accepts the author, title and 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");
    // TODO: pass in the first name and last name that are in the args parameter
    User author = new User("Jiho", "Song");

    // TODO: initialize the forum post with the user created above and a title and description of your choice
    ForumPost post = new ForumPost(author, "HowtoJava", "easy");
    forum.addPost(post);


  }

}

2 Answers

Alexandre Babeanu
Alexandre Babeanu
10,947 Points

Hello,

So first of all your constructors need to be public so they can be accessed in the Main class.

change private Forum, private User, and private ForumPost to public Forum public User and public ForumPost.

then when fixing the main.java :

you need to create a new User object with the first name and last name contained in the args array as parameters for the User constructor. NOT Jiho Song

change "Jiho","Song" to args[0], args[1]

Jiho Song
Jiho Song
16,469 Points

Thanks for teaching but what ensure that specifically name is going to be saved in argc[0], argc[1]? It could be argc[3] or even others?

Alexandre Babeanu
Alexandre Babeanu
10,947 Points

Sorry Jiho, I don't know. why don't you ask team tree house? Maybe it is related to the lesson. Good luck!

Jiho Song
Jiho Song
16,469 Points

However where does this program takes value from the user? It should input the info from user by somewhat method such as console.readLine, however i cant not find any. I sort of understand it not 100%

Alexandre Babeanu
Alexandre Babeanu
10,947 Points

taking value from the user is not in the scope of that prograam. It could be done in many various ways. You have to assume some external program retreives info from the user and formats it as an array. The array is then passed as a parameter to main(). Jiho this is just an exercise on constructors its not meant as a fully working prgram.

Alexandre Babeanu
Alexandre Babeanu
10,947 Points

If you found my response helpful please vote it up.