Using two for-loops - c#

This is an easy question but I'm still learning this language.
How we can write program that has parameters so that if the the number is 5, it will write
*
**
***
****
*****
I can do this:
*
*
*
*
Using this:
private void button1_Click(object sender, EventArgs e)
{
string message = " ";
for (int count = 0; count < numericUpDown1.Value; count++)
{
for (int m = 0; m < numericUpDown1.Value; count)
{
message += "*" + "\r\n";
}
}
}
I think I need the second for-loop, but I'm not sure what to do next.


if that's not a conceptual homework it would be much easier to solve this way:
for(int i=1; i<=n; i++)
Console.WriteLine(new string('*',i));


You need two loops (see note).
First (a) counts from 1 to 5.
Second (b) counts from 1 to a and adds a "*" each time.
private void button1_Click(object sender, EventArgs e)
{
string message = " ";
for (int count = 0; count < numericUpDown1.Value; count++)
{
for (int m = 0; m < count; m++)
{
message += "*";
}
message += "\r\n"
}
}
Note You can do it with one for loop. But personally I think the two loop version is clearer.
private void button1_Click(object sender, EventArgs e)
{
string line = "";
string message = " ";
for (int count = 0; count < numericUpDown1.Value; count++)
{
line += "*";
message += "\r\n" + line;
}
}


Try this :
private void button1_Click(object sender, EventArgs e)
{
string message = "";
for (int count = 0; count < numericUpDown1.Value; count++)
{
for (int m = 0; m <=count ; m++)
{
message += "*" ;
}
message += "\r\n";
}
}


Yo do not need two for-loops, try this instead
private void button1_Click(object sender, EventArgs e)
{
string message = "";
for (int count = 1; count < numericUpDown1.Value + 1; count++)
{
message += "".PadLeft(count,'*') + Environment.NewLine;
}
}


Try this, just another way to do it for learning:
private static void PrintStars(int num)
{
for (int i = 1; i <= num; i++)
{
for (int j = 1; j <= i; j++)
{
Console.Write("*");
}
Console.WriteLine();
}
}

Related

how can i adding up numbers from an array using the foreach loop

i've made an array with numbers.
i want to ad up the numbers form the array and show the result in a textbox.
i've to use the foreach loop.
i've already searched on the internet but i can't find anything that helped me.
this is my code:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void btnsortar_Click(object sender, EventArgs e)
{
//opdr 9
int[] getallen = { 4,5,9,8,31,44,76,63,88,59 };
int index = 1;
int lengteArray = getallen.Length;
tbsortar.Text = getallen[0].ToString();
while (index < lengteArray)
{
Array.Sort(getallen);
tbsortar.Text = tbsortar.Text + "," + getallen[index].ToString();
index++;
}
//opdr 10
string[] namen = { "kees", "jan", "piet", "henk" };
Array.Sort(namen);
int lengteArray1 = namen.Length;
tbopdr10.Text = namen[0];
for (int i=1; i<lengteArray1; i++)
{
string newLine = Environment.NewLine;
tbopdr10.Text = tbopdr10.Text +newLine + namen[i] ;
}
//opdr 11
double totaal = 0;
foreach(int getal in getallen)
{
//toaal van getallen is 392
totaal += getal;
tbopdr11.Text = tbopdr11.Text + totaal;
}
}
}

Try this:
int[] Numbers = { 1, 2, 3 };
int Result = 0;
for (int i = 0; i < Numbers.Length; i++)
{
Result += Numbers[i];
}
TextBox1.Text = System.Convert.ToString(Result);
The textbox's name is TextBox1.

can't you just use sum?
getallen.Sum()
https://dotnetfiddle.net/sTn1kp

How to randomly generate 1000 sequences of 6 digit number

I want to generate 1000 number randomly and put the result in a rich text box ,but the result I got from my code is just one number appearing in the rich text box !!
private Random _random = new Random();
int min = 000000;
int max = 999999;
string s;
private void Form1_Load(object sender, EventArgs e)
{
for (int i = 0; i < 1000; i++)
{
s = _random.Next(min, max).ToString("D6") + "\n";
}
richTextBox1.Text = s;
}

You are overriding the value of s each time you get your next number. Instead you have to add the number to a list. Something like this would work.
List<string> numbers = new List<string>();
private void Form1_Load(object sender, EventArgs e)
{
for (int i = 0; i < 1000; i++)
{
numbers.Add(_random.Next(min, max).ToString("D6"));
}
richTextBox1.Text = string.Join(Environment.NewLine, numbers);
}

As most of the answers here using the .net class Random i would not use it, because in a direct comparison it doesn't creates strong random numbers.
Example:
So if you want strong random numbers you should refrain from using Random and use the RNGCryptoServiceProvider from the namesapace System.Security.Cryptography
ExampleCode:
private RNGCryptoServiceProvider _random = new RNGCryptoServiceProvider ();
int min = 000000;
int max = 999999;
private void Form1_Load(object sender, EventArgs e)
{
int[] results = new int[1000];
var buffer = new byte[4];
int min = 100000;
int max = 999999;
for (int i = 0; i < results.Length; i++) {
while(results[i] < min || results[i] > max)
{
_random.GetBytes(buffer);
results[i] = BitConverter.ToInt32(buffer, 0);
}
richTextBox1.Text += results[i].toString();
}
}

You actually need to concatenate the result with previous calculated result, right now it is replacing the string value in s every time loop executes and you end up only with the last value in s, a quick fix is to use contatination using +:
for (int i = 0; i < 1000; i++)
{
s+= _random.Next(min, max).ToString("D6") + "\n"; // now it keeps previous values as well
}

Problem is that you actually overwrite at each iteration the string s. You need to append the number to the old ones.
for (int i = 0; i < 1000; i++)
{
s += _random.Next(min, max).ToString("D6") + "\n";
}
richTextBox1.Text = s;
You could also use AppendText method
for (int i = 0; i < 1000; i++)
{
richTextBox1.AppendText(_random.Next(min, max).ToString("D6") + "\n");
}
Suggestion by Matthew Watson: When generating such a large string it is very adviseable to use a StringBuilder. Is has much better performance than a normal concatenation of strings:
StringBuilder sb = new StringBuilder(8000);
for (int i = 0; i < 1000; i++)
{
sb.AppendLine(_random.Next(min, max).ToString("D6"));
}
richTextBox1.Text = sb.ToString();

s += _random.Next(min, max).ToString("D6") + "\n";
^
|
---- You're missing this plus sign

on this line of code you override the Text of richTextBox1
for (int i = 0; i < 1000; i++)
{
s = _random.Next(min, max).ToString("D6") + "\n";
}
richTextBox1.Text = s;
just change it to (add a + after s)
for (int i = 0; i < 1000; i++)
{
s += _random.Next(min, max).ToString("D6") + "\n";
}
richTextBox1.Text = s;

Note that the maxValue or Random.Next is exclusive, so 999999 is never genereted.
var numbers = Enumerable.Repeat(new Random(), 1000)
.Select(r => r.Next(1000000).ToString("D6")); // the same new Random() instance is used for all .Next
richTextBox1.Text = string.Join("\r\n", numbers);
Or a bit more efficient:
richTextBox1.Text = Enumerable.Repeat(new Random(), 1000).Aggregate(new StringBuilder(7000)
, (b, r) => b.AppendFormat("{0:D6}\n", r.Next(1000000))).ToString(0, 6999);

just You need to add ' + ' for the richtextbox1 as like below
try this one
private void Form1_Load(object sender, EventArgs e)
{
for (int i = 0; i < 1000; i++)
{
s = _random.Next(min, max).ToString("D6") + "\n";
richTextBox1.Text + = s;
}
}

How to output only a part of values from ListBox?

I would like to output only a part of items from listBox1 like:response.response.items[counter].first_name to lable_name.Text. How can I do that?
Part of method:
for (int counter = 0; counter < response.response.items.Count; counter++)
{
listBox1.Items.Add(response.response.items[counter].first_name + " " + response.response.items[counter].last_name + Environment.NewLine);
}
The way I output items to lable:
private void listBox1_DoubleClick(object sender, EventArgs e)
{
int count = listBox1.Items.Count -1;
for (int counter = count; counter >= 0; counter--)
{
if (listBox1.GetSelected(counter))
{
lable_name.Text= listBox1.Items[counter].ToString();
}
}
}

lable_name.Text = listbox1.Items[counter].ToString().Split(' ')[0];
could be one of the options ...
just make sure what charackter are qou spliting on as well as the text in string.

How to search and replace words in a WPF TextBox?

I've found several examples that do this but with richTextBox instead. Is it even possible to replace words in a multi-line TextBox?

you can do this for searchin' the next word automatically in textbox
int t = 0;
private void FindNext(object sender, RoutedEventArgs e)
{
for (int i = t; i < NoteText.Text.Length-SearchBar.Text.Length; i++)
{
string x = "";
for (int j = 0; j < SearchBar.Text.Length; j++)
{
if(SearchBar.Text[j] == NoteText.Text[i+j])
{
x += NoteText.Text[i + j] + "";
}
else
{
x = "";
}
}
if(x == SearchBar.Text)
{
t = i+1;
NoteText.Focus();
NoteText.SelectAll();
NoteText.Select(i, SearchBar.Text.Length);
break;
}
if(i==NoteText.Text.Length - SearchBar.Text.Length - 1)
{
MessageBox.Show("The search was completed");
t = 0;
}
s = t;
}
}

summing selected values of datagridview

I using this code for sum selected cells. Its work good but when user selecte cell where is letter is throws exceptions : ) how can i secure when in selectet cells is letters dont make sum
i asked same question but there i cannot add my code
private void dataGridView1_SelectionChanged(object sender, EventArgs e)
{
for (int i = 0; i < dataGridView1.SelectedCells.Count; i++)
{
if (!dataGridView1.SelectedCells.Contains(dataGridView1.Rows[i].Cells["cLoadName"]))
{
float nextNumber = 0;
float sumNumbers = 0;
nextNumber = float.Parse(dataGridView1.SelectedCells[i].FormattedValue.ToString());
sumNumbers += nextNumber;
tsslSumSelected.Text = "ჯამი: " + sumNumbers;
tsslTotalSelected.Text = "მონიშნული: " + dataGridView1.SelectedCells.Count.ToString();
}
else
{
}
}
}

private void dataGridView1_SelectionChanged(object sender, EventArgs e)
{
for (int i = 0; i < dataGridView1.SelectedCells.Count; i++)
{
if (!dataGridView1.SelectedCells.Contains(dataGridView1.Rows[i].Cells["cLoadName"]))
{
float nextNumber = 0;
float sumNumbers = 0;
if (float.TryParse(dataGridView1.SelectedCells[i].FormattedValue.ToString(), out nextNumber))
sumNumbers += nextNumber;
tsslSumSelected.Text = "ჯამი: " + sumNumbers;
tsslTotalSelected.Text = "მონიშნული: " + dataGridView1.SelectedCells.Count.ToString();
}
else
{
}
}
}

public void ComputeGridTot()
{
try
{
decimal qty= 0;
decimal price = 0;
decimal tax = 0;
decimal Total = 0;
for (int i = 0; i < drGrdView1.Rows.Count; i++)
{
if (drGrdView1.Rows[i].Cells[7].Value.ToString() == blcnt.ToString())
{
qty += Convert.ToDecimal(drGrdView1.Rows[i].Cells[3].Value);
price += Convert.ToDecimal(drGrdView1.Rows[i].Cells[4].Value);
tax += Convert.ToDecimal(drGrdView1.Rows[i].Cells[5].Value);
Total += Convert.ToDecimal(drGrdView1.Rows[i].Cells[6].Value);
}
}
lblGTax.Text = tax.ToString();
lblGQty.Text = qty.ToString();
lblGPrice.Text = price.ToString();
lblGTot.Text = Total.ToString();
}
catch
{
}
}

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