Getting more confused with constructor, method, objects and class

Question

I am learning constructor and objects and method on Java language. I understand the difference between non-argument and parameter constructor but I encounter a problem on my code that I can't seem to figure out.

I am writing a code for capturing the registration information. I create a class CompetitionEntry and inside the class, I insert 2 private attributes as private String projecTitle; and private int teamSize; and along with one class attribute as double feePerParticipant = 6.50; with the initial value of $6.50.

Then I create a no-argument constructor that I have initializes as projectTitle = "N/A"; and teamSize = 0;. An overloading constructor that initializes the attributes using the incoming arguments.

And I create the Mutator and Accessor method for the attribute teamSize but I want to ensure that it only except positive value. Lastly i create the method call computeTeamFee() that return the total fees by multiplying teamSize with feePerParticipant.

I wanted my code to get an output for the total team fee from the computeTeamFee(); method but I can't seem to find the problem and I need to initialize the object (using constructor) with the values "Super Tech" for the title and team size is 5.

And I can only change from the objects method to change the values and display the output.

Please help me. I'm getting more and more confused.

public class CompetitionEntry {

     private String projectTitle;
     private int teamSize;

     double feePerParticipant = 6.50;

     public CompetitionEntry () {

         this.projectTitle = "N/A";
         this.teamSize = 0;

      }

     public void setTeamSize(int teamSize) {

          //This part i not to sure how to read only positive value.
          if (this.teamSize <= 0) {

               System.out.println ("Negative value are not acceptable.")

          }
          else {

          this.teamSize = teamSize;

          }
     }

     public int getTeamSize() {
          return teamSize;
     }


     public double computeTeamFee() {

          double totalFee;
          totalFee = this.teamSize * feePerParticipant;

          return totalFee;

     }                  

     public static void main(String[] args) {

         CompetitionEntry obj = new CompetitionEntry ("Super Tech","5");  

         System.out.println("Title: " + obj.projectTitle);
         System.out.println("Team Size: " + obj.teamSize);


      } 
}

Answer 1

When you create the CompetitionEntry object, you are giving it the parameters "Super Tech" and "5" as inputs.

CompetitionEntry obj = new CompetitionEntry ("Super Tech", 5);
//P.S You put "5" instead of 5 (remove the quotations for integer 
//values as its not a string) as shown above

These input parameters for obj ("Super Tech" and "5") correspond with the inputs to the constructor (title and size)

public CompetitionEntry (String title, int size) {
    this.projectTitle = title;
    this.teamSize = size;
}

The constructor then sets projectTitle and teamSize to be equal to the inputs that went into the constructor.

There are some other mistakes in your codes such as missing a semi-colon in your setTeamSize function for the System.out.print line.