Basic programs of data_structure

Implementation to sort an array of size n where elements are in range from 0 to n2 – 1.

 

// A function to do counting sort of arr[] according to

// the digit represented by exp.

int countSort(int arr[], int n, int exp)

{

 

    int output[n]; // output array

    int i, count[n] ;

    for (int i=0; i < n; i++)

       count[i] = 0;

 

    // Store count of occurrences in count[]

    for (i = 0; i < n; i++)

        count[ (arr[i]/exp)%n ]++;

 

    // Change count[i] so that count[i] now contains actual

    // position of this digit in output[]

    for (i = 1; i < n; i++)

        count[i] += count[i - 1];

 

    // Build the output array

    for (i = n - 1; i >= 0; i--)

    {

        output[count[ (arr[i]/exp)%n] - 1] = arr[i];

        count[(arr[i]/exp)%n]--;

    }

 

    // Copy the output array to arr[], so that arr[] now

    // contains sorted numbers according to curent digit

    for (i = 0; i < n; i++)

        arr[i] = output[i];

}

 

 

// The main function to that sorts arr[] of size n using Radix Sort

void sort(int arr[], int n)

{

    // Do counting sort for first digit in base n. Note that

    // instead of passing digit number, exp (n^0 = 0) is passed.

    countSort(arr, n, 1);

 

    // Do counting sort for second digit in base n. Note that

    // instead of passing digit number, exp (n^1 = n) is passed.

    countSort(arr, n, n);

}

 

// A utility function to print an array

void printArr(int arr[], int n)

{

    for (int i = 0; i < n; i++)

        cout << arr[i] << " ";

}

 

// Driver program to test above functions

int main()

{

    // Since array size is 7, elements should be from 0 to 48

    int arr[] = {40, 12, 45, 32, 33, 1, 22};

    int n = sizeof(arr)/sizeof(arr[0]);

    cout << "Given array is \n";

    printArr(arr, n);

 

    sort(arr, n);

 

    cout << "\nSorted array is \n";

    printArr(arr, n);

    return 0;

}

Output:-

Given array is

40 12 45 32 33 1 22

Sorted array is

1 12 22 32 33 40 45

Create a animated "PENDULUM" in Java

//SniperNitesh
import java.awt.*;
import javax.swing.*;

public class Pendulum extends JPanel implements Runnable {

    private double angle = Math.PI / 2;
    private int length;

    public Pendulum(int length) {
        this.length = length;
        setDoubleBuffered(true);
    }

    @Override
    public void paint(Graphics g) {
        g.setColor(Color.WHITE);
        g.fillRect(0, 0, getWidth(), getHeight());
        g.setColor(Color.RED);
        int anchorX = getWidth() / 2, anchorY = getHeight() / 4;
        int ballX = anchorX + (int) (Math.sin(angle) * length);
        int ballY = anchorY + (int) (Math.cos(angle) * length);
        g.drawLine(anchorX, anchorY, ballX, ballY);
        g.fillOval(anchorX - 3, anchorY - 4, 7, 7);
        g.fillOval(ballX - 7, ballY - 7, 14, 14);
    }

    public void run() {
        double angleAccel, angleVelocity = 0, dt = 0.1;
        while (true) {
            angleAccel = -9.81 / length * Math.sin(angle);
            angleVelocity += angleAccel * dt;
            angle += angleVelocity * dt;
            repaint();
            try { Thread.sleep(15); } catch (InterruptedException ex) {}
        }
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(2 * length + 50, length / 2 * 3);
    }

    public static void main(String[] args) {
        JFrame f = new JFrame("Pendulum");
        Pendulum p = new Pendulum(200);
        f.add(p);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.pack();
        f.setVisible(true);
        new Thread(p).start();
    }
}