•// Reading/Writing, Operations,Loops

using System;

​

public class Program

{

    public static void Main()

    {

        // 1. RW

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        // In C#, Strings need double quotes (") e.g. "Hello"

        // Only use single quotes for chars (') e.g. 'A'

        Console.WriteLine("Hello!");

​

        //String username = Console.ReadLine();

        // Python: username = input()

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        //Console.WriteLine(username);

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        // R/W Done!

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        // 2. Operations

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        // Arithmetic

        int a = 0;

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        a = a + 2;

        a += 2; // This means the same thing

        Console.WriteLine("This is a: " + a);

        // A is 4 here

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        ++a; // This just increases a by one and assigns to a

        a++; // So does this

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        // So what's the difference?

        /* 

         * The first one, ++a, is called pre-increment

         * It will increment the value first, then be read

         * The second, a++, is called post-increment

         * It will increment the value after it has been read

         * 

         */

        Console.WriteLine("This is a: " + a);

        // A is 6

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        // Preincrement test

        Console.WriteLine(++a); // This SHOULD print 7

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        // Postincrement test

        Console.WriteLine(a++);  // This SHOULD ALSO print 7 (but after it becomes 8)

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        // You can do all of the above with subtract (-)

        // Note that --a, a-- is called decrement, not increment

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        // Multiplication (*) and Division (/) can do all of the above except they do not have

        // an equivalent 'pre/post multiple/divide' operator (i.e. there is no '**a')

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        a *= 2; // This should make a 16

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        // There is a modulo operator in C# as well

        // Python: a = a % 3

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        a = a % 3; // This should make a 1

        Console.WriteLine("This is a: " + a);

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        // These are all the arithmetic operations (above)

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        // Here are comparison operators

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        /*

         * == - test for equality

         * != - test for not-equality

         * >=  <= > < for lt, gt, lte, gte

         * 

         * All of this was in Python, also in C#

         */

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        // Here are the logical operators

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        /* and - &&

         * or - ||

         * not - !

         * 

         * So, in C#, we use symbols, not English

         */

​

        // Operations Done!

​

        // 3. Loops

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        // In Python, this while loop counts to 4 (thanks, Austin)

        /* 

         * a = 0

           while a != 5:

            print(a)

            a += 1

        */

​

        // In C#, this looks like this:

        int i = 0;

        while (i != 5)

        {

            Console.WriteLine(i);

            ++i;

        }

        // Does this count to 4 for you?

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        // This is a while loop

        bool logicalStatement = false;

        while (logicalStatement)

        {

            Console.WriteLine("Hello? This is the while loop.");

        }

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        // This is a do-while loop with the same condition

        do

        {

            Console.WriteLine("Hello? This is the do-while loop.");

        } while (logicalStatement);

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        // Notice that the print statement is executed ONCE and not again

        // This is because a do-while loop will ALWAYS execute its block at least once

        // After that, it checks the condition to know if it has to keep going

        // In practice, do-while loops are used only rarely

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        // For loop in Python? To count from 1 to 6.

        /* for num in range(1,7):

         *   print(num)

         */

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        // For loops in C# are slightly more syntactical

        // This is the same loop in C# code

        for (int num = 1; num < 7; ++num)

        {

            Console.WriteLine(num);

        }

​

        // The first statement initializes variables

        // The second is the logical condition to check to know whether to keep going

        // The final statement is how to update the variable

        for (int num = 10, anotherInteger = 0 ; num > 0; num--, anotherInteger -=1)

​

        {

            Console.WriteLine(num);

            // Try to avoid doing anything else with num inside the loop

            // Because you need it to keep count

            // num = 10; // This would be very bad

            anotherInteger = num * 2;

            Console.WriteLine(anotherInteger);

        }

​

        // WHILE, DO WHILE, FOR LOOPS DONE?

​

​

    }

}

​