var-Implicitly Typed Local Variables - CSharp Language Basics

CSharp examples for Language Basics:var

  1. HOME
  2. CSharp
  3. Language Basics
  4. var

Introduction

If the compiler can infer the type from the initialization expression, you can use the keyword var in place of the type declaration.

For example: 

var x = "hello";
var y = new System.Text.StringBuilder();
var z = (float)Math.PI;

This is precisely equivalent to: 

string x = "hello";
System.Text.StringBuilder y = new System.Text.StringBuilder();
float z = (float)Math.PI;

Because of this direct equivalence, implicitly typed variables are statically typed.

For example, the following generates a compile-time error: 

var x = 5;
x = "hello";    // Compile-time error; x is of type int

Related Tutorials