Java address book. How to prevent duplicate contacts in my code?

Question

switch(menuChoice) {

case 1: 
    System.out.println(\"Enter your contact\'s first name:\\n\");
    String fname = scnr.next();
    System.out.println(\"Enter your cont         


        

Answer 1

Here is the code for keeping out duplicate ID's.

public void addContact(Person p) {

    for(int i = 0;  i < ArrayOfContacts.size(); i++) {
        Person contact = ArrayOfContacts.get(i);
        if(contact.getID() == p.getID()) {
            System.out.println("Sorry this contact already exists.");
            return; // the id exists, so we exit the method. 
        }
    }

    // Otherwise... you've checked all the elements, and have not found a duplicate
    ArrayOfContacts.add(p);

}

If you would like to change this code to keep out duplicate names, then do something like this

public void addContact(Person p) {
    String pName = p.getFname() + p.getLname();
    for(int i = 0;  i < ArrayOfContacts.size(); i++) {
        Person contact = ArrayOfContacts.get(i);
        String contactName =  contact.getFname() + contact.getLname(); 
        if(contactName.equals(pName)) {
            System.out.println("Sorry this contact already exists.");
            return; // the name exists, so we exit the method. 
        }
    }

    // Otherwise... you've checked all the elements, and have not found a duplicate
    ArrayOfContacts.add(p);

}