Method must have a return type

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!

2 Replies

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DANIEL PEREIRA8y ago
Thak you, Ravi! I tried that but then I get

"The type 'Rextester.Program' already contains a definition for 'WaveGenerator'"

So, I should change the second Wavegenerator to something else, right? But I'm concerned that later in the code we have

private void btnGenerateWave_Click(object sender, EventArgs e)
{
string filePath = @"C:\Users\cliente\Desktop\teste.wav";
WaveGenerator wave = new WaveGenerator(WaveExampleType.ExampleSineWave);
wave.Save(filePath);
SoundPlayer player = new SoundPlayer(filePath);
player.Play();
}

Now, the WaveGenerator we have here is the public class?
Ravi Patel8y ago
Hi ,

Method must have return type even if method does not return any value you have to write void before method name

Change from

public WaveGenerator(WaveExampleType type) TO
public void WaveGenerator(WaveExampleType type)