Bubble sort · Java, before term starts

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Core exercise

Write triABulles(int[] tableau) that sorts the array in ascending order and returns it.

Example · step-by-step trace · Bubble sort, swap by swap

At each pass, the large values “bubble up” towards the end of the array.

for (int tour = 0; tour < t.length - 1; tour++) {
    for (int i = 0; i < t.length - 1 - tour; i++) {
        if (t[i] > t[i + 1]) {
            int temporaire = t[i];
            t[i] = t[i + 1];
            t[i + 1] = temporaire;
        }
    }
}

ligne	variables	tableau	explication
3	tour = 0, i = 0	[5] [1] 4 2	5 > 1? Yes → they must be swapped.
6	tour = 0, i = 0	[1] [5] 4 2 (échange)	Swap done, via the temporary variable.
3	tour = 0, i = 1	1 [5] [4] 2	5 > 4? Yes → swap.
6	tour = 0, i = 1	1 [4] [5] 2 (échange)	The 5 keeps moving up.
3	tour = 0, i = 2	1 4 [5] [2]	5 > 2? Yes → swap.
6	tour = 0, i = 2	1 4 [2] [5] (échange)	End of the first pass: the largest value is in its final place. That is why the next pass stops earlier.
3	tour = 1, i = 0	[1] [4] 2 5	1 > 4? No → nothing is touched.
3	tour = 1, i = 1	1 [4] [2] 5	4 > 2? Yes → swap.
6	tour = 1, i = 1	1 [2] [4] 5 (échange)	The array is sorted, but the algorithm does not know it yet.
3	tour = 2, i = 0	[1] [2] 4 5	1 > 2? No. Last pass, no swap: the sort is finished.

A workshop goes here: you write and run code in it. It requires JavaScript.

Starting code

Exercices.java

import java.util.Arrays;

public class Exercices {

    public static void main(String[] args) {
        int[] t = { 5, 1, 4, 2, 8 };
        System.out.println(Arrays.toString(triABulles(t)));
    }

    public static int[] triABulles(int[] tableau) {
        // TODO
        return tableau;
    }
}

The core exercise is validated in the workshop, which requires JavaScript.

Hint 1

Compare each pair of neighbours and swap them if they are out of order; start again until no swap takes place. Swapping requires a temporary variable.