So I'm a C++ programmer student, and I'm starting to learn Java, and I would like to read a class called Candidate with two string values (Name and ID), and I would like to store these Candidates in a container.
What would be the best container to use in this situation, and what could I use to store these values while sorting them by Name.
Since I'm used to STL library, I was thinking about something like a vector or a list.
Thanks!
What exactly is the use case you are looking for? The best container would depend on whether your usage including insertions, removals, reading in order or not, etc.
If you're just interested in Java equivalents to the C++ STL classes, the Java equivalent of std::vector is ArrayList (see Equivalent of std::vector in Java? ). They are both dynamic arrays.
If I'm not mistaken, the Java equivalent of std::list is LinkedList.
This answer gives a nice overview on the topic: Linked List vs Vector
If you're looking for a list that was inserted and deleted while maintaining sorted order, you'd likely be best of with TreeSet as mentioned in the comments above.
You probably are best served by using a PriorityQueue with this constructor https://docs.oracle.com/javase/7/docs/api/java/util/PriorityQueue.html#PriorityQueue(int,%20java.util.Comparator)
Then you can simply instantiate it via like:
new PriorityQueue<Candidate>(10, new Comparator<Candidate>() {
@Override
public int compare(final Candidate o1, final Candidate o2) {
return Candidate.getName().compareTo(o2.getName());
}
});
10 would just be an example capacity here, you can choose whatever fits your use case.
The priority queue will automatically order your Candidate objects according to their name on every insert since you specified a Comparator that does so for you.
You can use a TreeSet to insert into a container that is maintained in a sorted order. However, this is a set, not a list, so you cannot access by index.
A simple Approach:
//Declare your Candidate class as:
class Candidate
{
int id;
String name;
Candidate(int id,String name)
{
this.id=id;
this.name=name;
}
public int getId()
{
return this.id;
}
public String getName()
{
return this.Name;
}
}
class Main
{
public static void main(String args[])
{
ArrayList<Candidate> al=new ArrayList<Candidate>();
al.add(new Candidate(1,"ABC"));
al.add(new Candidate(2,"XYZ"));
al.add(new Candidate(3,"PQR"));
Collections.sort(al,new SortByName());
System.out.println(al);
}
}
//Declare a Comparator to sort by Name
class SortByName implements Comparator<Candidate>
{
public int compare(Candidate c1,Candidate c2)
{
return c1.getName().compareTo(c2.getName());
}
}
// As you have posted in your question that you are beginner to java, and as per your requirement you want to have container to store objects of class, and then sort them by thier field name. Hence, I have used ArrayList from Collections class which is very simple to use and learn for beginner's like, I would reckon you to go through some basic concept's of arraylist class,Comparator,Collections method etc.
Thank you all guys for all the answers, after a research of the proposals you've granted me, I've finally decided to use a TreeSet just because I found that was the most useful to me in this case. Thanks again!
