sorting - Java - Selection Sort Algorithm

Question

I have some questions about selection sort.I'm a little bit confused.

 int [] arr = {5,4,3,2,1}; // This is my array
    int min = 0;

    for(int i = 0;i<arr.length;i++)
    {
        //Assume first element is min
        min = i;//Selection sort algorithm says that find the minimum in the
                // array, but first element is not minimum.What's point here?
        for(int j = i + 1;j<arr.length;j++)
        {
            int temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
            System.out.println(arr[i]);//I print the in ascending order 
        }
    }

Output is :

4
3
2
1
4
3
2
4
3
4

What's wrong ?

Answer 1

selection sort is about finding the min value in each step of loop. you didn't find out the min value (by if statement maybe), just simply exchange the value in your inner loop. so you actually didn't do a sort.

correction based on your implementation:

final int[] arr = { 5, 4, 3, 2, 1 }; // This is my array
    int min;
    for (int i = 0; i < arr.length; i++) {
        // Assume first element is min
        min = i;
        for (int j = i + 1; j < arr.length; j++) {
            if (arr[j] < arr[min]) {
                min = j;

            }
        }
        if (min != i) {
            final int temp = arr[i];
            arr[i] = arr[min];
            arr[min] = temp;
        }
        System.out.println(arr[i]);// I print the in ascending order
    }

this should give you output:

1
2
3
4
5