StdRandom, StdOut, Insertion cannot be resolved

Question

This code should implement sorting.
I have 3 errors:
"StdRandom cannot be resolved",
"StdOut cannot be resolved",
"Insertion cannot be resolved".
May be there are some libraries to import?

public class randomDoubles 
{
public static void main(String[] args)
{

    int N = Integer.parseInt(args[0]);
    Double[] a = new Double[N];
    for(int i = 0; i < N; i++)
        a[i] = StdRandom.uniform(); // error: StdRandom cannot be resolved
    Insertion.sort(a);                  // error: Insertion cannot be resolved
    for (int i = 0; i < N; i++)
        StdOut.println(a[i]);       // error: StdOut cannot be resolved
}
}

Solution 1

you need to use the following files

http://introcs.cs.princeton.edu/java/stdlib/StdRandom.java.html

http://algs4.cs.princeton.edu/11model/StdOut.java.html

Solution 2

You're definitely missing some imports of non-standard libraries here. If you want to compile and use this code as it is, you should ask your professor where to find the libraries and how to import them.

But if you just want an example of doing approximately what's shown here with standard java libraries, the following might suffice:

import java.util.Arrays;
import java.util.Random;

public class RandomDoubles {

    public static void main(String[] args)
    {

        int N = Integer.parseInt(args[0]);
        Double[] a = new Double[N];
        Random rand = new Random();
        for(int i = 0; i < N; i++)
            a[i] = rand.nextDouble();
        Arrays.sort(a);
        for (int i = 0; i < N; i++)
            System.out.println(a[i]);
    }

}

Comments

[Atcold]

And how do you import them?

[Baimyrza Shamyr]

Just create new files with these contents with names of the classes in the same folder with main file, and it will definitely run.

[rv1822]

If you are using DrJava, you can include stdlib.jar in the classpath, Preferences -> Extra Classpath -> Add. Check introcs.cs.princeton.edu/java/stdlib