Introducing C# 9: Top-level programs

Introduction

C# 9 introduces a super fun feature: Top-level programs. What’s a Top-level program ? This is a simpler way to write your program on its top level: a simpler Program.cs file

Before C# 9 and with C# 9

In your main program you have been able to write whatever you want, for example:

• async calls (obviously)
• accessing args (obviously)
• local functions (obviously again !)

Imagine now, being able to do the same but in a simpler way ? it’s still possible with Top-level program feature. You will still be able to do the same:

No needs anymore to write class Program and void (or async Task) Main(string[] args). You will be able in the same way to call async code, accessing args before and even declare local functions and more!

Great isn’t it ? 😉