For (A Lesson; On C#; Loops)

Hello readers,

Michael here, and today’s post will be all about loops in C#. We’ll go over the for-loop, foreach-loop and while-loop!

If you learned about loops through some of my previous programming tools, great! However, for those who may not know, loops in programming are simple sets of directions for the program to repeat X amount of times until a certain condition is met.

For (A Piece; On C#; Loops)

The first type of loop we’ll cover is a simple C# for loop. Here’s an example of a C# for loop:

for (int m = 5; m <= 30; m+=5)
{
    Console.WriteLine(m);
}

5
10
15
20
25
30

In this loop, I have the for (statement 1; statement 2; statement 3) with the respective statements being int m = 5 (setting initial loop value to 5), m <= 30 (setting the loop-ending condition to the point where m is less than or equal to 30), and m+=5 (indicating that m should be incremented by 5 during each loop iteration). After the for statement, I have the body of the loop, which prints out each successive value from 5 to 30 in increments of 5.

  • Just so you remember, the three statements in a C# for loop are (in order) the initial value-setter, the loop-ending condition, and the action that should be performed during each loop iteration. Also, the statements in the for loop need to be separated by semicolons.

Foreach (Lesson in Loops)

The next type of C# loop we’ll iterate through (coder joke) is the foreach loop. Here’s an example of a foreach loop below:

string[] states = ["Tennessee", "Florida", "California", "New Mexico", "Arizona", "Ohio", "Indiana"];

foreach (string s in states)
{
    Console.WriteLine(s);
}

Tennessee
Florida
California
New Mexico
Arizona
Ohio
Indiana

In this example, I’m iterating through the states array using the foreach loop. Unlike the for loop, the foreach loop only requires one statement-(array type element in array). In this statement, you’ll need to include the array type, indicator value for each element in the array (s in this case) and the name of the array. In this case, I used foreach (string s in states).

While (C# Loop Runs)

Last but not least, let’s explore C# while loops. You may recognize while loops from other programming tools you know about (like Python) and in C#, while loops do the same thing-run the loop over and over WHILE a certain condition is True.

Here’s an example of a simple C# while loop:

int o = 2;

while (o <= 100)
{
    Console.WriteLine(o);
    o *= 2;
}

2
4
8
16
32
64

In this example, we have a simple C# while loop that sets the initial value-o-to 2. The loop will then multiply o by 2 for each iteration until o hits the highest possible value allowed by the loop condition. In other words, o will keep multiplying itself by 2 until it gets to 64, as 64*2 (128) will end the loop as 128 is greater than 100.

Now, how would you structure a C# while loop? The syntax is quite simple-while (condition to keep loop running) { code block to execute }.

Do (Loop Code) While Loop = Running

So we just explored the C# while loop. However, did you know there’s a variation of the C# while loop called the do-while loop. It works just like a while loop with one major difference-do-while loops will always be executed at least once as they always check whether the condition is still true before performing the next loop iteration. Here’s our while loop example from above converted into a do-while loop

int f = 2;

do  
{
    Console.WriteLine(f);
    f *= 2;
} 
while (f <= 100);

2
4
8
16
32
64

How would you structure a do-while loop. Easy-do { code block to execute } while (condition to test loop)! As you can see from the output, our do-while loop returned the same six values as our while loop above.

For (Infinite; Loop; Encounters)

Yes, just as with other languages we’ve covered (Python and R for two), it is possible to have the infinite loop encounter in C# as well. Here’s an example of that:

while (true)
{
    Console.WriteLine("Michael's Programming Bytes");
}

The loop above is a simple example of an infinite C# loop. Since the while (true) statement will never stop the loop, it will just keep going, and going, and going…unless of course you write a break statement in the loop to stop it after X iterations or something like that.

For (Nested; Loops) For (In; C#)

Yes, it is possible to have nested loops in C#, just as it’s possible to have nested loops in other programming languages. Here’s a simple example of a C# nested loop:

for (int t = 2; t <= 20; t*=2)
{
    for (int n = 5; n <= 30; n+=5)
    {
        Console.WriteLine(t * n);
    }
}

10
20
30
40
50
60
20
40
60
80
100
120
40
80
120
160
200
240
80
160
240
320
400
480

This loop will print out all possible products of t and n through each iteration of the nested loop pair. The outermost loop-the one with t-runs first while the innermost loop-the one with n-runs second. The reason you see 24 outputs on this page is because the amount of iterations a nested loop has is the product of the amount of iterations for each individual loop. In this case, since the t loop runs four times and the n loop runs six times, we get 24 total iterations of the nested loop (4*6=24).

Here’s the link to the script for today’s post on my GitHub-https://github.com/mfletcher2021/blogcode/blob/main/Loops.cs. Note that I did include the infinite loop example here but if you want to effectively test the other loops, you can “turn off” the infinite loop simply by commenting it out of the code.

Thanks for reading,

Michael

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