Var can be of any type, it is simply an alias and its type is determined by the compiler. There is no performance issues with using the var keyword. Var simply makes your programs shorter and easier to read. Please note that you cannot create a new var type.
var wholeNumber = 0; // is same as: int wholenumber = 0;
// This wont work, it will throw an error.
The name variable "var name;" will throw an error because the compiler doesn't know what variable type it is, as there is no such type actually exists, it aliases other types. To use the var keyword the variable must be assigned a value at time of creation. To make the name variable work it must be assigned like this:
var name = "Get Coding";
// is same as: string name = "Get Coding";
The var keyword can even be used when calling a function that returns a type. This is because the compiler knows the type of the returning variable.
static void Main()
var name = GetName();
// Calls GetName() function which returns a string.
// var name is a string type.
private string GetName()
return "Get Coding";