How to import files in C#?

Question

I'm writing a simple C# program. I have two files, ClassA.cs and ClassB.cs .

Each of these files implements its respective class.

I want to create an object of ClassB inside a method of ClassA.

My code looks like this:

ClassA.cs

using System;

public class ClassA {

    public static void Main(string[] args) {

        Console.WriteLine("Starting...");
        ClassA classA = new ClassA();
    }

    public ClassA() {

        ClassB classB = new ClassB();
    }
}

ClassB.cs

using System;

public class ClassB {

    public ClassB() 
    {
        Console.WriteLine("ClassB created.");
    }
}

How can I compile this project now? When I try to do csc ClassA.cs ClassB.cs I get the error The type or namespace name 'ClassB' could not be found .

I'm guessing I'm missing something like an import statement from Java or include from C++. What's the equivalent in C#?

Also, I'm not using an IDE. Only writing the files in a text editor and manually compiling / running in the console (windows).

Answer 1

I created 2 files in the same folder ( c:\\code\\egcsc ): ClassA.cs and ClassB.cs , with the respective contents you have shown.

Then:

c:\code\egcsc>dir
 Volume in drive C is (irrelevant)
 Volume Serial Number is (irrelevant)

 Directory of c:\code\egcsc

28/03/2018  12:26    <DIR>          .
28/03/2018  12:26    <DIR>          ..
28/03/2018  12:24               253 ClassA.cs
28/03/2018  12:25               126 ClassB.cs
               2 File(s)            379 bytes
               2 Dir(s)  (irrelevant) bytes free

c:\code\egcsc>csc ClassA.cs ClassB.cs
Microsoft (R) Visual C# Compiler version 2.8.0.62716 (e205ae18)
Copyright (C) Microsoft Corporation. All rights reserved.


c:\code\egcsc>ClassA.exe
Starting...
ClassB created.

So; it worked fine; you need to double-check what you have. Note: using a tool like VSCode or Visual Studio (there are free versions) would make this a lot easier...