Implementing Selection Sort in Java

I did this sort function in C++ for Linked List

void sort()
{
    node* ctr;
    node* innerctr;
    info temp;
    node* max;
    ctr = start;
    while(ctr!=NULL)
    {
        innerctr=ctr->next;
        max=ctr;
            while(innerctr!=NULL)
            {

                if((innerctr->student.name) > (max->student.name))
                {
                    max=innerctr;

                }


                innerctr=innerctr->next;


            }

            //swapping...


        ctr开发者_StackOverflow=ctr->next;
    }
}

I need to do something similar in Java and I want to use the LinkedList ready class but I am a bit confused because there are no pointers.

Check java.util.Collections.sort. There's no need to implement sorting and such in Java, it's all in the JDK.

With as few modifications as possible, nearly the same thing in Java:

class Student {String name = "Joe Doe";}
class Node {
    Node next;
    Student student;
}
class Info {}
public class NodeSorter {

    Node start; 

    void sort()
    {
        Node ctr;
        Node innerctr;
        Info temp;
        Node max;
        ctr = start;

        while (ctr != null)
        {
            innerctr = ctr.next;
            max=ctr;

            while (innerctr != null)
            {
                if ((innerctr.student.name).compareTo (max.student.name) > 0)
                {
                    max = innerctr;
                }
                innerctr=innerctr.next;
            }
            //swapping...
            ctr = ctr.next;
        }
    }
}

• some dummy classes (Student, Info)
• Node would normally be generic, not fixed to Student.
• classnames with Capitals.
• methods and attributes are just delimited with dot
• comparision with compareTo (for non-numbers)

And here is the improved version, with Type "Student" as parameter for the Node:

class Student implements Comparable <Student> {
    String name = "Joe Doe";
    public int compareTo (Student other) {
        if (other == null) return 1;
        return name.compareTo (other.name);
    }   
}
class Node <T> {
    Node <T> next;
    T value;
}
class Info {}
public class NodeSorter {

    Node <Comparable> start;    

    void sort ()
    {
        Node <Comparable> ctr;
        Node <Comparable> innerctr;
        Info temp;
        Node <Comparable> max;
        ctr = start;

        while (ctr != null)
        {
            innerctr = ctr.next;
            max=ctr;

            while (innerctr != null)
            {
                if ((innerctr.value).compareTo (max.value) > 0)
                {
                    max = innerctr;
                }
                innerctr=innerctr.next;
            }
            //swapping...
            ctr = ctr.next;
        }
    }
}

The problem with the unspecified 'start' is inherited from you.

• I don't know what means > for name in your example
• Below code uses selecting min index not max index like in your case - so you should change a bit this solution. But idea is still the same

source from this site

public static void selectionSort2(int[] x) {
    for (int i=0; i<x.length-1; i++) {
        int minIndex = i;      // Index of smallest remaining value.
        for (int j=i+1; j<x.length; j++) {
            if (x[minIndex] > x[j]) {
                minIndex = j;  // Remember index of new minimum
            }
        }
        if (minIndex != i) { 
            //...  Exchange current element with smallest remaining.
            int temp = x[i];
            x[i] = x[minIndex];
            x[minIndex] = temp;
        }
    }
}