Use types, input, and strings
Store typed values, read console input, and format output.
- Use common C# types, Console.ReadLine, parsing, and interpolation.
C# checks types at compile time. int stores whole numbers, double stores floating-point numbers, bool stores true or false, and string represents text. var asks the compiler to infer a local variable type from its initializer; it does not make the variable dynamically typed. Console.ReadLine returns text, so numeric input must be parsed, for example with int.Parse.
1using System;
2
3class Program
4{
5 static void Main()
6 {
7 string name = Console.ReadLine() ?? "friend";
8 Console.WriteLine($"Welcome, {name}!");
9 }
10}Input: Riley Welcome, Riley!
The ?? operator provides a fallback if the left side is null. C# nullable reference types add compile-time warnings about possible null values when enabled; they help communicate intent but do not add runtime null checks automatically.
Key takeaways
C# is statically typed, including locals declared with var.
Console input arrives as text and needs parsing for numbers.
Use interpolation to format values into strings.
Lesson quiz
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