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Java Java Objects Delivering the MVP Forum

welsen ho
welsen ho
1,330 Points

Still can't solve the problem

Is there something wrong with my code?

error shows: ./Main.java:13: error: constructor User in class User cannot be applied to given types; User author = new User(args[2]); ^ required: String,String found: String reason: actual and formal argument lists differ in length ./Main.java:15: error: incompatible types: String cannot be converted to User ForumPost post = new ForumPost("new","code","finished"); ^ Note: JavaTester.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details. Note: Some messages have been simplified; recompile with -Xdiags:verbose to get full output 2 errors

Forum.java
public class Forum {
  private String topic;

  // TODO: add a constructor that accepts a topic and sets the private field topic

  public String getTopic() {
    return topic;
  }

  public Forum(String topic){

    this.topic = 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;


  public 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;

  // 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");
    // TODO: pass in the first name and last name that are in the args parameter
    User author = new User(args[2]);
    // TODO: initialize the forum post with the user created above and a title and description of your choice
    ForumPost post = new ForumPost("new","code","finished");
    forum.addPost(post);


  }

}

1 Answer

Yanuar Prakoso
Yanuar Prakoso
15,196 Points

Hi Welsen

You almost done it. You just need to repair your Main class:

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(args[2]);<-- this is wrong since args starts indexing from [0], you should change it to:
     User author = new User(args[0], args[1]);//<--remember args[0] = firstName, args[1] = lastName
    // TODO: initialize the forum post with the user created above and a title and description of your choice
//  ForumPost post = new ForumPost("new","code","finished");<--this is wrong it supposed to be
    ForumPost post = new ForumPost(author, "Java", "Forum about Java Programing");
// please note that the topic "Java" and the description is entirely up to you to input it just an example
    forum.addPost(post);


  }

}

I hope this can help a little.