Variables and types

C# variables have an explicit type: int count = 0;. Unlike JavaScript, you cannot silently change a variable from int to string without a compile error. var still infers a fixed type at compile time—like auto in C++.

Common scalar types

• int, long — integers
• double, float, decimal — floating point (decimal for money)
• char — single UTF-16 code unit
• bool — true or false
• string — immutable text (reference type on the heap)

var and initialization

var count = 10;        // inferred as int
double ratio = 0.75;
bool ok = true;
string name = "Ada";

Value types live on the stack or inline in structs; reference types like string point to heap objects managed by the GC—contrast with manual memory in C++.

Important interview questions and answers

1. Q: var vs dynamic?
   A: var is compile-time type inference; dynamic defers binding to runtime (rare in typical C#).
2. Q: Value type vs reference type?
   A: Value types copy by value; reference types copy a reference—mutations through one reference affect the shared object.

Self-check

1. What type does var infer from an integer literal?
2. Is string a value type or reference type?

Pitfall: var still picks a fixed type at compile time—unlike dynamic typing in JavaScript.