Question

I’m trying to implement a Discrete Fourier Transformation algorithm for a project I’m doing in school. But creating a class is seeming to be difficult(which it shouldn’t be).
I’m using Visual Studio 2012.

Basically I need a class called Complex to store the two values I get from a DFT; The real portion and the imaginary portion.

This is what I have so far for that:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SoundEditor_V3
{
    public class Complex
    {
        public double real;
        public double im;

        public Complex()
        {
            real = 0;
            im = 0;
        }
    }
}

The problem is that it doesn’t recognize the constructor as a constructor, I’m just learning C#, but I looked it up online and this is how it’s supposed to look.
But it recognizes my constructor as a method.

Why is that?
Am I creating the class wrong?

It’s doing the same thing for my Fourier class as well. So each time I try to create a
Fourier object and then use it’s method…there is no such thing.

example, I do this:

Fourier fou = new Fourier();
fou.DFT(s, N,  amp, 0);

and it tells me fou is a ‘field’ but is used like a ‘type’
why is it saying that?

Here is the code for my Fourier class as well:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SoundEditor_V3
{
   public class Fourier
   {

        //FOURIER
        //N = number of samples
        //s is the array of samples(data)
        //amp is the array where the complex result will be written to
        //start is the where in the array to start
        public void DFT(byte[] s, int N, ref Complex[] amp, int start)
        {
            Complex tem = new Complex();
            int f;
            int t;

            for (f = 0; f < N; f++)
            {

                tem.real = 0;
                tem.im = 0;

                for (t = 0; t < N; t++)
                {
                    tem.real += s[t + start] * Math.Cos(2 * Math.PI * t * f / N);
                    tem.im -= s[t + start] * Math.Sin(2 * Math.PI * t * f / N);

                }
                amp[f].real = tem.real;
                amp[f].im = tem.im;

            }
        }

        //INVERSE FOURIER
        public void IDFT(Complex[] A, ref int[] s)
        {
            int N = A.Length;
            int t, f;
            double result;
            for (t = 0; t < N; t++)
            {
                result = 0;
                for (f = 0; f < N; f++)
                {
                    result += A[f].real * Math.Cos(2 * Math.PI * t * f / N) - A[f].im * Math.Sin(2 * Math.PI * t * f / N);
                }
                s[t] = (int)Math.Round(result);
            }
        }
    }
}

I’m very much stuck at the moment, any and all help would be appreciated. Thank you.

edit:

this is where I’m trying to access all my classes:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace SoundEditor_V3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        string filename;
        NAudio.Wave.WaveStream waveStream;

        private NAudio.Wave.DirectSoundOut sout = null;

        private void openToolStripMenuItem_Click(object sender, EventArgs e)
        {

            OpenFileDialog open = new OpenFileDialog();
            open.Filter = "Wave File (*.wav)|*.wav";
            if (open.ShowDialog() != DialogResult.OK)
            {
                return;
            }
            waveStream = new NAudio.Wave.WaveFileReader(open.FileName);
            filename = open.FileName;
            sout = new NAudio.Wave.DirectSoundOut();
            sout.Init(new NAudio.Wave.WaveChannel32(waveStream));

        }

        //Play
        private void Play_btn_Click(object sender, EventArgs e)
        {
            sout.Play();
        }

        //Stop
        private void Stop_btn_Click(object sender, EventArgs e)
        {
            sout.Stop();
            waveStream.Position = 0;
        }

        //Pause
        private void Pause_btn_Click(object sender, EventArgs e)
        {
            sout.Pause();
        }



        //display fourier
        //N = number of samples(length of array)
        //s is the array of samples(data)
        //amp is the array where the complex result will be written to
        //start is the where in the array to start
        static int N = 8;
        byte[] s = {1,2,3,4,5,6,7,8};


        Complex[] amp = new Complex[N];

        Fourier xfo = new Fourier();



        //xfo.DFT(s, N,  amp, 0); 

    }
}

Answer 1

Thank you for all your help; I actually ended up figuring everything out.
I couldn’t access methods in the area I was trying to access them in. I had to put them inside a method block because this was all being coded inside a form.
That’s my understanding anyway.

But again, thank you for all your suggestions, they were all helpful.