Question

(Sort ArrayList) Write the following method that sorts an ArrayList:

  public static <E extends Comparable<E>>

void sort(ArrayList<E> list)

Write a program to test the method with three different arrays:

Integers: 2, 4, and 3;

Doubles: 3.4, 1.2, and -12.3;

Strings: "Bob", "Alice", "Ted", and "Carol"

Answer 1

SOURCE CODE:

*Please follow the comments to better understand the code.

**Please look at the Screenshot below and use this code to copy-paste.

***The code in the below screenshot is neatly indented for better understanding.



import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;

// Create the class
public class TestGenerics
{
    public static <E extends Comparable<E>> void sort(ArrayList<E> list)
    {
        // we can use the method in collections class
        Collections.sort(list);
    }

    // TEST THE METHOD
    public static void main(String[] args) {
        Integer[] integers={2,4,3};
        Double[] doubles={3.4,1.2,-12.3};
        String[] strings={"Bob", "Alice", "Ted","Carol"};

        // sort integers and print
        ArrayList<Integer> numbers=new ArrayList<>(Arrays.asList(integers));
        System.out.println("Before Sort: "+numbers);
        sort(numbers);
        System.out.println("After Sort: "+numbers);

        // sort doubles and print
        ArrayList<Double> doubleal=new ArrayList<>(Arrays.asList(doubles));
        System.out.println("Before Sort: "+doubleal);
        sort(doubleal);
        System.out.println("After Sort: "+doubleal);

        // sort strings and print
        ArrayList<String> stringsal=new ArrayList<>(Arrays.asList(strings));
        System.out.println("Before Sort: "+stringsal);
        sort(stringsal);
        System.out.println("After Sort: "+stringsal);

    }
}

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