Every program you decide to write will use data at some point. I am not talking about databases nor web services. I am talking about plain simple variables.
To put it simple: Variables are nothing more than a named place in the memory where you store something to use later. Think of a box with a name in it and which accepts only certain kind of objects. For example: A box named "balls" which accepts only spherical objects.
In C# we have the following types:
- Integral: sbyte, byte, short, ushort, int, uint, long, ulong, and char
- Floating point: float and double
- Decimal: decimal
- Boolean: true or false values, as assigned
- Nullable: Nullable data types
Define your variables
You can define your variables in 2 ways:
- [type] [variable_name], [variable_name]; (eg.: string name, surname;)
- [type] [variable_name] = [variable_value]; (eg.: string name = "Joe";)
The first one is used when you want to define one or many variables at once, without setting a value. The second alternative can be used when you want to initialize the variable already during its declaration.
As mentioned above, we can define our variables without initializing it (setting a value). In case we do it, however, we need to pay attention to the default values which each object has. See below:
- bool: false
- byte: 0
- char: '\0'
- decimal: 0.0M
- double: 0.0D
- float: 0.0F
- int: 0
- long: 0L
- sbyte: 0
- short: 0
- uint: 0
- ulong: 0
- ushort: 0
Notice the letters beside some of those default values. Normally the compiler will require you to specify what kind of value you are assigning to a type. And in order to tell it to the compiler that you want to assign a, for example, double instead of a float you need to add the D in the end of the number.