Updated 5_variables.txt

Hertz authored
revision a0db3cfe9b8e898cafbf93bda2a548ffd3ce0177
# 5 - Variables

### Learning Objectives :

- Learn what a variable is
- Learn how to declare variables
- Learn how to assign a value to variables
- Learn how to get input from the console
- Learn the difference between variables declaration and assignment

### Introduction

In the previous chapter we learned about some key building blocks that made up a Fantom program. Using expressions and operators we can manipulate data and make calculations. What if we want to do multiple operations on one value? What if we want save data that we use, so we can access it easily later? That's the whole point of variables.

### Variables

In programming **variables are storage for data**. Just like in math variables may change their value. Variables can be used to store the value of an expression or just hold a literal value. InFantom variables are only allowed to hold *one* type of data. For example a variable that is declared to hold a string value can hold an int value. What do we mean by decaring and holding values? I will explain in the next few sections.

### Declaring A Variable

**Declaring a varible is just creating a variable**. When variables are declared space in memory is set aside for that variable to store its data. The ammount of memory allocated for that variable depends on the type of data that variable is going to hold. To declare a new variable in Fantom you use the following syntax ;

DataType varible_name := value;

You specify what type of data a varible is going to hold by giving it a datatype. **Again, datatype is the type of data a variable can hold.** Some basic datatypes and what they represent are :

`Int`: Represents and integer. ( Positive and Negative Whole numbers )

`Bool`: Represents a boolean value.(true or false)
`Char`: Represents a single character.
`Str` : Represents a string (array) orf characters.