Method must have a return type

Question

Folks, I am an engineer who learned Pascal back in my day and I am trying to get around object-oriented languages, with limited success. I'm just getting started on C#, so please bear with me.

 

I copied some code I found at https://blogs.msdn.microsoft.com/dawate/2009/06/24/intro-to-audio-programming-part-3-synthesizing-simple-wave-audio-using-c/ and now I am trying to run it, but there's something wrong at line 128.

 

The original code was

public enum WaveExampleType
{
ExampleSineWave = 0
}

public class WaveGenerator
{
// Header, Format, Data chunks
WaveHeader header;
WaveFormatChunk format;
WaveDataChunk data;
///
}

public WaveGenerator(WaveExampleType type)
{
// Init chunks
header = new WaveHeader();
format = new WaveFormatChunk();
data = new WaveDataChunk();

// Fill the data array with sample data
switch (type)
{
case WaveExampleType.ExampleSineWave:
// Number of samples = sample rate * channels * bytes per sample
uint numSamples = format.dwSamplesPerSec * format.wChannels;
// Initialize the 16-bit array
data.shortArray = new short[numSamples];
int amplitude = 32760; // Max amplitude for 16-bit audio
double freq = 440.0f; // Concert A: 440Hz
// The "angle" used in the function, adjusted for the number of channels and sample rate.
// This value is like the period of the wave.
double t = (Math.PI * 2 * freq) / (format.dwSamplesPerSec * format.wChannels);
for (uint i = 0; i < numSamples - 1; i++)
// Fill with a simple sine wave at max amplitude
for (int channel = 0; channel < format.wChannels; channel++)
{
data.shortArray[i + channel] = Convert.ToInt16(amplitude * Math.Sin(t * i));
}
}
// Calculate data chunk size in bytes
data.dwChunkSize = (uint)(data.shortArray.Length * (format.wBitsPerSample / 8));
break;
}
}

But I get the return type error for line 1. (line 128 at this online editor: http://rextester.com/KOVPK29971). What is wrong here? I get that the intention was to leave room for a future implementation of a different WaveExampleType using the switch/case thing, but why does one have to write anything inside the parenthesis in line 1 and why does it have the same name as the class?

 

I know it's a very simple thing, and I realize the point is I don't understand the whole point behind creating a class and then something else with the same name. Remember, I learned Pascal. Could someone please point how to correct the code and the idea behind it? Thanks in advance!