Programming Lessons: Let's learn a little of C# - Lesson 03

Hello Guys

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Some days ago I started a new topic. I wanna teach how to program a little. As you probably know I'm a software developer so I wanna bring some of the stuff that I do daily. With this topic I do not wanna do something hard to understand but the basic concepts of programming.

We'll start with a simple topics and the language that we'll use is C#.

About C#

C# is a simple, modern, general-purpose, object-oriented programming language developed by Microsoft within its .NET initiative led by Anders Hejlsberg. This tutorial covers basic C# programming and various advanced concepts related to C# programming language.

First of all, if you wanna try the examples that I'll provide you can use this site to program online C#. Alternatively, you can install the free version on Visual Studio, the best tool to program C# here.

Image Source

Lesson 03: Data Type

In C# the basic kind of variables are:

• Value types
• Reference types

Value Type

Value type variables can be assigned a value directly (Derived from System.ValueType). The value types directly contain data. Some examples are int, char, and float, which stores numbers, alphabets, and floating point numbers, respectively. When you declare an int type, the system allocates memory to store the value.
source

Type	Represents	Range
bool	Boolean value	True or False
byte	8-bit unsigned integer	0 to 255
char	16-bit Unicode character	U +0000 to U +ffff
decimal	128-bit precise decimal values with 28-29 significant digits	(-7.9 x 1028 to 7.9 x 1028) / 100 to 28
double	64-bit double-precision floating point type	(+/-)5.0 x 10-324 to (+/-)1.7 x 10308
float	32-bit single-precision floating point type	-3.4 x 1038 to + 3.4 x 1038
int	32-bit signed integer type	-2,147,483,648 to 2,147,483,647
long	64-bit signed integer type	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
sbyte	8-bit signed integer type	-128 to 127
short	16-bit signed integer type	-32,768 to 32,767
uint	32-bit unsigned integer type	0 to 4,294,967,295
ulong	64-bit unsigned integer type	0 to 18,446,744,073,709,551,615
ushort	16-bit unsigned integer type	0 to 65,535

Code

// Initializing Value Types
int myInt;  

// Invoke default constructor for int type.
myInt = new int();    

// Assign an initial value, 0 in this example.  
myInt = 0;

You can find more information here.

Reference Type

The reference types do not contain the actual data stored in a variable, but they contain a reference to the variables. In other words, they refer to a memory location. You can find more information here.

C# also provides the following built-in reference types:

• dynamic
• object
• string

String Type

The string type is one of the most used when programming.

"The string type represents a sequence of zero or more Unicode characters. string is an alias for String in the .NET Framework. Although string is a reference type, the equality operators (== and !=) are defined to compare the values of string objects, not references. This makes testing for string equality more intuitive." source

string s1 = "Hello  ";
string s2 = "World.";

// Concatenate s1 and s2. This actually creates a new string object and stores it in s1, releasing the reference to the original object.
s1 += s2;

System.Console.WriteLine(s1);
// Output: Hello World.

You can find more information here.

Hope you enjoy the first lesson

@criptomaster