Thread: Exercise 149

Hi, I'm having trouble with this exercise. Any help would be appreciated. I think I only have one part wrong, but I'm not sure. I think it has to do with checking for x in ArrayList a. I'm pretty sure I'm not checking for "x" correctly. The error I'm getting is "not a statement: for (x : a) {" or when I put "Person x : a" I get an error that says "modifier expected"

Here is the exercise instructions and prewritten code:

 
In the following definition of the Person class, complete the definition of the includeMeIn method. This takes as its only argument an ArrayList a that contains nothing but Person objects. It adds the instance to the ArrayList, provided only that there is not already a Person object in the ArrayList with the same name:
 
public class Person
{
  private String myName;
 
  public Person( String name )
  {
    myName = name;
  }
 
  public String getName()
  {
    return myName;
  }
 
 
//my code would go here
 
//here is what I have so far:
 
public void includeMeIn( ArrayList<Person> a )
 
{
 
    for (Person x : a){
 
        if (Person.new == x){
 
            a.remove(x);
 
        }
 
    }
 
}
 
}
 
public class MainClass
{
  public static void main( String[] args )
  {
 
//and here is some other prewritten code that I can modify:
 
ArrayList<Person> people = new ArrayList<Person>();
 
Person p1 = new Person( "fred" );
 
Person p2 = new Person( "eric" );
 
Person p3 = new Person( "jason" );
 
Person p4 = new Person( "davina" );    
 
Person p5 = new Person( "eric" );
 
 
 
p1.includeMeIn( people );
 
p2.includeMeIn( people );
 
p3.includeMeIn( people );
 
p4.includeMeIn( people );
 
p5.includeMeIn( people );
 
 
 
for ( Person p : people )
 
  System.out.println( p.getName() );
 
 //That part was modifiable
 
  }
}

for (x : a) {" or when I put "Person x : a" I get an error that says "modifier expected"

I believe that you have compilation error in this part of your code.
That is not a valid syntax.

if (Person.new == x)

May I know what are you trying to check with that statement?

From what I can see, the includeMeIn method is to check if the name stored within the Person object is already in the ArrayList a that is passed into this method.

Take a look at the ArrayList API doc at ArrayList (Java Platform SE 7 ). This class contains a method that can help you do the checking.