# Chapter 2. Living with Variability — Declaring Value-Type Variables

In This Chapter

**Visiting the train station — the C# variable as storage locker****Using integers — you can count on it****Handling fractional values — what's half a duck?****Declaring other types of variables — dates, characters, strings****Handling numeric constants — Π in the sky****Changing types — cast doesn't mean toss****Letting the compiler figure out the type — var magic**

The most fundamental of all concepts in programming is that of the variable. A C# variable is like a small box in which you can store things, particularly numbers, for later use. (The term *variable* is borrowed from the world of mathematics.)

Unfortunately for programmers, C# places several limitations on variables — limitations that mathematicians don't have to consider. This chapter takes you through the steps for declaring, initializing, and using variables. It also introduces several of the most basic *data types* in C#.

# Declaring a Variable

When the mathematician says, "*n* is equal to 1," that means the term *n* is equivalent to 1 in some ethereal way. The mathematician is free to introduce variables in a willy-nilly fashion. For example, the mathematician may say this:

x = y^{2}+ 2y + y if k = y + 1 then x = k^{2}

Programmers must define variables in a particular way that's more demanding than the mathematician's looser style. For example, a C# programmer may write the following bit of code:

int n; n = 1;

The first line means, "Carve off a small amount of storage in the computer's ...

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