Program.cs

// PART 1 -- "HELLO WORLD" & STRING

// Hello World
Console.WriteLine("Hello, World!");

// Console.WriteLine("Text" + Var); & Console.WriteLine($"Text{}");
string aFriend = "Bill";
Console.WriteLine(aFriend);

// "$" called string interpolation
aFriend = "Maria";
Console.WriteLine("Hello " + aFriend);
Console.WriteLine($"Hello {aFriend}");

string firstFriend = "Agus";
string secondFriend = "Budi";
Console.WriteLine($"My Friends are {firstFriend} and {secondFriend}");
Console.WriteLine("My Friends are " + firstFriend + " and " + secondFriend);

// String Length >> .Length
Console.WriteLine($"The name {firstFriend} has letters {firstFriend.Length}");
Console.WriteLine($"The name {secondFriend} has letters {secondFriend.Length}");

// TrimStart(), TrimEnd(), Trim()
string greeting = "   Hello World   ";
Console.WriteLine($"[{greeting}]");
Console.WriteLine($"[{greeting.Trim()}]");

string trimStartGreeting = greeting.TrimStart();
Console.WriteLine($"[{trimStartGreeting}]");

string trimEndGreeting = greeting.TrimEnd();
Console.WriteLine($"[{trimEndGreeting}]");

string trimGreeting = greeting.Trim();
Console.WriteLine($"[{trimGreeting}]");

// Replace
string friends = $"my friends are {firstFriend} and {secondFriend}";
Console.WriteLine(friends);
Console.WriteLine(friends.Replace("Agus", "Ujang"));
Console.WriteLine(friends);

Console.WriteLine(friends.Replace(secondFriend, "Ujang"));
Console.WriteLine(friends.Replace(secondFriend, firstFriend));
Console.WriteLine($"my friends are {firstFriend}, {secondFriend}, and {secondFriend}".Replace(secondFriend, firstFriend));

string sayHello = "Hello World";
Console.WriteLine(sayHello);
Console.WriteLine(sayHello.Replace("Hello", "Hi"));
sayHello = sayHello.Replace("Hello", "Greetings");
Console.WriteLine(sayHello);

// all Caps & all Lower
Console.WriteLine(sayHello.ToUpper());
Console.WriteLine(sayHello.ToLower());

// Search Strings
string songLyrics = "you say goodbye and I say hello";
Console.WriteLine(songLyrics.Contains("goodbye"));
Console.WriteLine(songLyrics.Contains("Greetings"));

// StartsWith , EndsWith
Console.WriteLine(songLyrics.StartsWith("you"));
Console.WriteLine(songLyrics.EndsWith("hello"));
Console.WriteLine($"songLyrics end with 'goodbye' = {songLyrics.EndsWith("goodbye")}");

// PART 2 -- NUMBERS

WorkWithIntegers();
OrderPrecedence();
Modulo();
Precisions();
MaxMin();
workWithDoubles();
workWithDecimals();

int a = 2100000000;
int b = 2100000000;
// long c = checked(a + b);
// Console.WriteLine(c);
long c = (long)a + (long)b;
Console.WriteLine(c);

void WorkWithIntegers()
{
    int a = 18;
    int b = 6;
    int c = a + b;
    Console.WriteLine(c);

    // substract
    c = a - b;
    Console.WriteLine(c);

    // multiplication
    c = a * b;
    Console.WriteLine(c);

    // division
    Console.WriteLine(a / b);
}

void OrderPrecedence()
{
    int a = 5;
    int b = 4;
    int c = 2;
    Console.WriteLine(a + b * c);
    Console.WriteLine((a + b) * c);
    Console.WriteLine((a + b) / c);
}

void Modulo()
{
    int a = 7;
    int b = 4;
    int c = 3;
    int d = (a + b) / c;
    int e = (a + b) % c;
    Console.WriteLine($"quotient: {d}");
    Console.WriteLine($"remainder: {e}");
}

void Precisions()
{
    double a = 42.1;
    float b = 38.2f;
    double c = a + b;
    Console.WriteLine(c);

    decimal d = 42.1m;
    decimal e = 38.2m;
    decimal f = d + e;
    Console.WriteLine($"{d} + {e} = {f}");
}

void MaxMin()
{
    int max = int.MaxValue;
    int min = int.MinValue;
    int max2 = max + max;
    Console.WriteLine($"The range of integers is {min} to {max}");
    Console.WriteLine($"what if.. max + 1 = {max + 2}");
    Console.WriteLine($"what if.. max + max = {max2}");
    Console.WriteLine($"what if.. max + min = {max + min}");
    Console.WriteLine($"what if.. max - min = {max - min}");

    // max + 1 = min + 0
    // max + 2 = min + 1
    // max - min = max + max + 1
}

void workWithDoubles()
{
    double dMax = double.MaxValue;
    double dMin = double.MinValue;
    Console.WriteLine($"The range of double is {dMin} to {dMax}");

    double third = 1.0 / 3.0;
    Console.WriteLine(third);
}

void workWithDecimals()
{
    decimal min = decimal.MinValue;
    decimal max = decimal.MaxValue;
    Console.WriteLine($"The range of the decimal type is {min} to {max}");

    double a = 1.0;
    double b = 3.0;
    Console.WriteLine(a / b);

    decimal c = 1.0M;
    decimal d = 3.0M;
    Console.WriteLine(c / d);
}

// PART 3 -- BRANCH AND LOOPS

ExploreIf();
WhileLoops();
doWhile();
forLoops();

void ExploreIf()
{
    int a = 5;
    int b = 3;
    bool myTest = a + b > 10; // will be true or false
    if (myTest) // if true / myTest == 1
    {
        Console.WriteLine($"{a + b} is greater than 10");
    }
    else
    {
        Console.WriteLine($"{a + b} is not greater than 10");
    }

    int c = 4;
    if ((a + b + c > 10) && (a > b))
    {
        Console.WriteLine($"{a + b + c} is greater than 10");
        Console.WriteLine($"And the first number({a}) is greater than the second({b})");
    }
    else
    {
        Console.WriteLine($"{a + b + c} is not greater than 10");
        Console.WriteLine($"Or the first number({a}) is not greater than the second({b})");
    }

    if ((a + b + c > 10) || (a > b))
    {
        Console.WriteLine($"{a + b + c} is greater than 10");
        Console.WriteLine($"Or the first number({a}) is greater than the second({b})");
    }
    else
    {
        Console.WriteLine($"{a + b + c} is not greater than 10");
        Console.WriteLine($"And the first number({a}) is not greater than the second({b})");
    }
}

void WhileLoops()
{
    int counter = 0;
    while (counter < 5)
    {
        counter++; // print 1 - 5
        Console.WriteLine(counter);
        //counter++; print 0 - 4
    }
}

void doWhile()
{
    int counter = 0;
    do
    {
        Console.WriteLine(counter);
        counter++;
    } while (counter < 5);
}

void forLoops()
{
    int length = 5;
    for (int i = 0; i < length; i++)
    {
        if (i == 3)
            Console.WriteLine(i);
    }

    for (int row = 1; row < 11; row++)
    {
        for (char column = 'a'; column < 'k'; column++)
        {
            Console.WriteLine($"The cell is ({row}, {column})");
        }
    }
}
// shift + alt + F to format the code