How to Program a Hello World String Array For Loop in C# (C Sharp) with Microsoft Visual C#

Use Microsoft Visual C# to create a Hello World program that uses a For Loop to display String Array elements in a MessageBox.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Microsoft Visual C# 2008 Express (free)

1. 

   Note: This article assumes you have installed Microsoft Visual C# 2008 Express Edition. You may download it for free from here: http://www.microsoft.com/express/download/
   
   Open Microsoft Visual C#. Click on "Project..." to the right of Create in the Recent Projects area of the Start Page.

2. 

   The New Project window will open. Click on "Windows Forms Application", enter a Name, and click OK.
   
   By default, the only form in the project will be called "Form1" and you will be in Design mode for that form.

3. 

   Hover over the Toolbox on the left side of the screen and the Toolbox will automatically expand. Click and drag a Button control, under the Common Controls category, onto the form.

4. 

   Double click the button and you will now be in the code window for Form1. The method for the button click will already be created.

5. 

   Add our loop within the button1_Click method.
   
   // Classic Hello World Example:
   string[] MyStringArray = { "Hello", "World!" };
   
   for (int i = 0; i < MyStringArray.Length; ++i)
   {
   MessageBox.Show(MyStringArray[i]);
   }
   
   This 'for' loop will use an integer variable called "i" to loop through an array of strings. For each element in the array, it will pop-up a message box and display the string in the box. The string displayed will be the element of the array with the same number as the integer i:
   
   When i = 0, MyStringArray[i] = MyStringArray[0] = "Hello".
   When i = 1, MyStringArray[i] = MyStringArray[1] = "World!".
   
   The 'for' loop has 4 parts: initialize, compare, process, and increment.
   
   In our example "initialize" is setting the integer i to the value 0:
   
   int i = 0;
   
   Notice that i starts at 0. This is because the first element in an array is numbered as 0.
   
   Our "compare" compares the value of i to the length of the string. The length of the string is 2 so the loop will be executed two times:
   
   i < MyStringArray.Length;
   
   Note: Length is a property of the Array class and returns an Integer that can be compared to the integer i. If you hover over objects in Visual Studio 2008, you will get a context pop-up with extremely valuable information about the object.
   
   The "process" step pops up a MessageBox and displays the string:
   
   MessageBox.Show(MyStringArray[i]);
   
   Finally, i is incremented by 1:
   
   ++i
   
   Immediately after the increment, the comparison portion of the loop executes again.

6. 

   Go up to the toolbar and run the program by clicking on the Start Debugging (f5) play button. The form will take a moment and then pop up. Clicking on the button1 will display the MessageBoxes with our strings in it.
   
   NOTE: If you got any kind of error after clicking the play button, you probably made a syntax error when typing the code. Programming is a precise science. Reread the code until you find and correct the error and try again.

Tips & Warnings

• Play around with the Help. Tons of good stuff in there.
• You might get addicted to C#. Watch out Java and C++ folks!!!