Contents:

• Variables
• Types
• if
• for
• foreach
• Arrays
• Lists
• Functions
• Console

Variables:

To use variables you need to declare they type before use:

// <VARIABLE_TYPE> <VARIABLE_NAME>;
int n;

Types:

• int - integer e.g. -1, 0 100,
• bool - logic, can be either true or false,
• double (and float with lower precision) - real numbers, e.g. -1.2, 0.5, 1000.2,
• char - character, e.g. 'a', 'b', 'c', '0', '-',
• string - string of characters, e.g. "word", "a" (single sign string), "" (empty string),

Basic Operations:

// assignment "="
i = 0 ;

// declaration with initialization (create variable with initiale value)
int i = 0;

// addition, multiplication, division
c = a + b/2.0 +(a+1)/4;

// exponentiation (a^b)
Math.Pow(2,3); // gives 8

// square root:
Math.Sqrt(4); // gives 2

if

if(CONDITION)
{
    INSTRUCTIONS_IF_TRUE;
}

if/else

if(CONDITION)
{
    INSTRUCTIONS_IF_TRUE;
}
else
{
    INSTRUCTIONS_IF_FALSE;
}

if/else/if/else/if

You can chain as many i/else statements as you want:

if(C1)
    INSTRUCTIONS1;
else if(C2)
    INSTRUCTIONS2;
else if(C3)
    INSTRUCTIONS3;
else if(C4)
    INSTRUCTIONS4;
else
    INSTRUCTIONS_ELSE;

for (repeat something n times)

Syntax:

for( INITIALIZATION; CONDITION; STEP)
{
    INSTRUCTIONS;
}

Example

for( int i =0; i < 10; i++)
{
    Console.WriteLine(i);
}

Result:

0
1
2
3
4
5
6
7
8
9

foreach

Iterate a container (e.g. list or array) without indexing:

Syntax:

foreach( TYPE VARIABLE in CONTAINER)
{
    INSTRUCTIONS;
}

Example

List<int> my_list = new List<int>(){0,1,2,3,4,5,6,7,8,9};
foreach(int element in my_list)
{
    Console.WriteLine(element);
}

Result:

0
1
2
3
4
5
6
7
8
9

Arrays

• array type is BASE_TYPE[] e.g. int[], char[], string[] (array of integers, chars, strings etc.)
• lists containt elements of one type
• list's size cannot be changed after its creation (you can create a list of arbitrary size)
• to get size of the list use list.Length (no parentheses)
• arrays are initially filled with 0 (or 0 equivallent for nonnumerical types)

Creating a new array of integers (filled with 0) with n elements:

int[] tab = new int[n];

Creating an array with some values ( e.g. 1, 2, 3 )

int[] ar = new int[]{1, 2, 3};

Lists

• lists containt elements of one type
• list's size can be changed (e.g. by adding or removing) elements
• to get current size of the list use list.Count()

Creating an empty list of integers:

List<int> my_list = new List<int>();

Creating a list with some values ( e.g. 1, 2, 3 )

List<int> my_list = new List<int>(){1, 2, 3};

Misc:

Sorting

// Sorts a list in increasing order e.g. 1, 2, 3, 4 ,5 ...1000:
my_list.Sort();

Maximum and minimum value

int minimum = my_list.Mint();
int maximum = my_list.Max();

Printing and Reading (Console)

Write something:

Console.Write("Something")

Write something and end a line:

Console.WriteLine("Something")

Read a single line:

string the_line = Console.ReadLine();

Read a single key:

char key = Console.ReadKey();

Functions

Syntax

public static TYPE NAME([ARGUMENTS])
{
    INSTRUCTIONS;
    return X; // Required when TYPE is not 'void'
}

Examples

A function with no arguments that rreturns nothing and prints "hello"

public static void PrintHello()
{
    Console.WriteLine("hello");
}

A function that adds 2 numbers and returns the result

pblic static int add(int a, int b)
{
    return a+b;
}