laceywalkerr/fortune_teller

Anatomy of a C# Program

This is a high-level overview of the basic structure of a C# program. Much of what is covered here will be confusing, but don't worry we will cover it in more detail as we move throughout the course.

File Structure

Every C# program is made up of at least two files: a project file and a C# file.

For example, a "Fortune Telling" app might have this structure.

FortuneTeller/
├── FortuneTeller.csproj
└── Program.cs

The *.csproj file is the project file. It contains configuration information about the application. There is only one project file per project.

A *.cs file is a C# source code file. This is where your C# code goes. There can be many *.cs files. A large project could easily have hundreds or more.

In addition to these files you will also find two folders called bin and obj. These folders contain the output of compiling your C# code.

Program.cs

Program.cs is usually the starting point of you C# program. It contains a class called Program with method called Main. The Main method is always where the code starts executing.

using System;

namespace FortuneTeller
{
    class Program
    {
        static void Main(string[] args)
        {
            string fortune = "Everything will be ok.";
            Console.WriteLine(fortune);
        }
    }
}

Let's walk through this code

using System;

This is the way we "import" parts of the .net class library. The System "namespace" contains the Console object that we use later in the program.

namespace FortuneTeller

A namespace is a collection of related classes.

class Program

Almost all C# code must be contained inside a class. It is convention to use the same name for the class and the *.cs file.

static void Main(string[] args)

Main is a "method" in the Program class. A method is a function that exists inside a class. Main is a "static" method. This means we do not need to create a Program object in order to use it.

string fortune = "Everything will be ok.";
Console.WriteLine(fortune);

These lines make up the "body" of the Main method. The "body" of a method contains the executable C# code. Here we create a string variable and print it to the Console.

Notes: Made app using dotnet new console -o FortuneTeller2

Run app in console using dotnet run