Using nested for-loop

Question

I'm trying to use for loop.

If the input is 3, the result going to be:

1**
*2*
**3

So I used this code

void button1_Click(object sender, EventArgs e) {
    string message = " ";
    int value = numericUpDown1.Value;
    for(int count = 0; count < value; count++) {
        for(int m = -2; m < value; m++) {
            message += "*";
        }
        message += "\r\n";
    }
    MessageBox.Show(message);
}

I used the two for-loops but i could not fix it to show the number, but it give me

***
***
***

forgot to tag it as homework ?

Habib
– Habib

2012-07-25 04:14:44 +00:00
Commented Jul 25, 2012 at 4:14 — Habib
– Habib, Commented Jul 25, 2012 at 4:14
Your number will be your count variable +1

Mark Hall
– Mark Hall

2012-07-25 04:20:42 +00:00
Commented Jul 25, 2012 at 4:20 — Mark Hall
– Mark Hall, Commented Jul 25, 2012 at 4:20

jtimperley · Accepted Answer · 2012-07-25 04:18:23Z

3

int digitCount = 3;
string message = " ";
for (int round = 1; round <= digitCount; round++)
{
    for (int digit = 1; digit <= digitCount; digit++)
    {
        if (digit == round)
        {
            message += digit;
        }
        else
        {
            message += "*";
        }
    }

    message += "\r\n";
}

answered Jul 25, 2012 at 4:18

jtimperley

2,55414 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Clinton Ward Over a year ago

declare this instead string message;

Tomas Grosup · Accepted Answer · 2012-07-26 06:52:23Z

1

private string StarNumbers(int input)
    {
        var range = Enumerable.Range(1, input);
        var sb = new StringBuilder(input*input);
        foreach (var number in range)
        {
            var line = String.Format("{0}{1}{2}", new string('*', number - 1), number, new string('*', input - number));
            sb.AppendLine(line);
        }
        return sb.ToString();
    }

EDIT:

This code for input=500 : 2ms

(5ms for input 1 000)

Code using += string concatenation for input=500 : 33 468ms (all it does is garbage collection)

(running it for several minutes for input 1 000 and still nothing)

edited Jul 26, 2012 at 6:52

answered Jul 25, 2012 at 6:58

Tomas Grosup

6,5343 gold badges33 silver badges45 bronze badges

5 Comments

jtimperley Over a year ago

Your proposed solution is over engineered and harder to read thus more prone to bugs. Also, your String.Format uses more resources than concatenating string in such a simple scenario. The size of your declared string builder is off by a constant equal to 2xinput, thus it needs to be expanded, thus taking extra resources (you didn't account for new lines). Simplicity is king.

Tomas Grosup Over a year ago

Actually you are wrong in the resources thing, you can easily measure the difference ;)

Tomas Grosup Over a year ago

The stringbuilder needs to be expanded just once, with += new string is created each time.

jtimperley Over a year ago

For Fun: You can measure the difference because you've read the String.Format code? Analyzed the work that is required to parse out your place holders and re-concatenate the strings for you? I didn't care enough to correct every mistake you made but a "non-beginner" would perform three appends to the string builder which is optimized for concatenating strings. P.S. Your solution is still overkill.

jtimperley Over a year ago

:) I fixed the loop of someone who appears to be learning to code with requirements which by all accounts appear trivial. At no point did I claim my solution to be optimized, note the simple scenario statement above. I do however claim that any solution which has the .Net framework create an enumeration with a for-each loop is overkill. Wait, is that three legitimate reasons for overkill... Humm... :)

Collectives™ on Stack Overflow

Using nested for-loop

2 Answers 2

1 Comment

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related