CSharp/C# Tutorial - C# var

If the compiler can infer the type from the initialization expression, we can use the keyword var to declare variable type.

For example:

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

This is equivalent to:

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

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