Functions C# concept with real time

Functions are not a C# concept, they are provided ever since C programming language and even before that. Functions are used to create a block of statements that are to be executed whenever needed. Suppose, you want to write a code that saves an image of a person. But the logic is different, you change the name of the person too. You can write the code like this,

stringname=Guid.NewGuid().ToString()+"_"+file.Name;
File.WriteAllBytes($"~/Images/{name}",imageBytes);
stringname=Guid.NewGuid().ToString()+"_"+file.Name;
File.WriteAllBytes($"~/Images/{name}",imageBytes);
stringname=Guid.NewGuid().ToString()+"_"+file.Name;
File.WriteAllBytes($"~/Images/{name}",imageBytes);
stringname=Guid.NewGuid().ToString()+"_"+file.Name;
File.WriteAllBytes($"~/Images/{name}",imageBytes);

These four can be done just the way they are. You don't need to worry about anything at all. But consider a case where you have to change the logic of the name saving, for that you will have to update the logic in 4 different areas and you may also forget to do so. In such cases, you create functions and you call them and pass the imageData to it. Something like this,

voidsaveFile(byte[]imageData,stringname){
stringname=Guid.NewGuid().ToString()+"_"+name;
File.WriteAllBytes($"~/Images/{name}",imageBytes);
}

Now when you are going to update this, you will only have to update the things in one place only. Every update will be made just here. Now I will answer your specific questions:

You pass parameters when you have to save variable data or use variable data. Such as in my case of sending the byte array to the function.
When your function can work without a parameter, such as when just printing Hello world.
1. voidsayHello(){
2. Console.WriteLine("Helloworld!");
3. }
Data types are always required. You cannot omit data types.
1. voidfunc(a){
2. //Won'tcompile.
3. }
Out is a special case in C# where you specify that the data is not assigned, but is about to be assigned in the function and the output must be saved in that parameter which can be used outside the boundary of the function.
1. intdata;
3. voidfunc(outintdata){
4. data=10;
5. }
7. Console.WriteLine(data);//Outputs10
Typically, structures (int, date time etc.) are passed as value type but this would allow .NET to pass the data to the object as if it was reference type.

I will recommend learning more about functions from MSDN as they have an excellent guide available for beginners in C#.https://msdn.microsoft.com/en-us/library/ms173114.aspx. There are many other types of functions in C# too, such as extension functions and you will learn them from MSDN.

1 Reply

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Afzaal Ahmad Zeeshan10y ago
Accepted answer
Functions are not a C# concept, they are provided ever since C programming language and even before that. Functions are used to create a block of statements that are to be executed whenever needed. Suppose, you want to write a code that saves an image of a person. But the logic is different, you change the name of the person too. You can write the code like this,
stringname=Guid.NewGuid().ToString()+"_"+file.Name;
File.WriteAllBytes($"~/Images/{name}",imageBytes);
stringname=Guid.NewGuid().ToString()+"_"+file.Name;
File.WriteAllBytes($"~/Images/{name}",imageBytes);
stringname=Guid.NewGuid().ToString()+"_"+file.Name;
File.WriteAllBytes($"~/Images/{name}",imageBytes);
stringname=Guid.NewGuid().ToString()+"_"+file.Name;
File.WriteAllBytes($"~/Images/{name}",imageBytes);
These four can be done just the way they are. You don't need to worry about anything at all. But consider a case where you have to change the logic of the name saving, for that you will have to update the logic in 4 different areas and you may also forget to do so. In such cases, you create functions and you call them and pass the imageData to it. Something like this,
voidsaveFile(byte[]imageData,stringname){
stringname=Guid.NewGuid().ToString()+"_"+name;
File.WriteAllBytes($"~/Images/{name}",imageBytes);
}
Now when you are going to update this, you will only have to update the things in one place only. Every update will be made just here. Now I will answer your specific questions:
You pass parameters when you have to save variable data or use variable data. Such as in my case of sending the byte array to the function.
When your function can work without a parameter, such as when just printing Hello world.
voidsayHello(){
Console.WriteLine("Helloworld!");
}
Data types are always required. You cannot omit data types.
voidfunc(a){
//Won'tcompile.
}
Out is a special case in C# where you specify that the data is not assigned, but is about to be assigned in the function and the output must be saved in that parameter which can be used outside the boundary of the function.
intdata;
voidfunc(outintdata){
data=10;
}
Console.WriteLine(data);//Outputs10
Typically, structures (int, date time etc.) are passed as value type but this would allow .NET to pass the data to the object as if it was reference type.
I will recommend learning more about functions from MSDN as they have an excellent guide available for beginners in C#.https://msdn.microsoft.com/en-us/library/ms173114.aspx. There are many other types of functions in C# too, such as extension functions and you will learn them from MSDN.