[RESOLVED] for loop question

[Crash893]

im having trouble with the santax of the for loop in C#


in vb.net it would be something like

For index = 0 To table.Columns.Count - 1 Step 1
some stuff

Next

in c#

im getting stuck

/code
int index = table.columns.count -1;

For index ( how do i tell it to step down by -1 till 0)
{
some stuff
}

[ComputerJy]

for (index = 0 ; index < table.Columns.Count ; index++){
     SomeStuff;
}

[jmcilhinney]

This:

For i As Integer = 0 To myTable.Rows.Count - 1 Step 1
   '...
Next i

equals this:

for (int i = 0; i <= myTable.Rows.Count - 1; i++)
{
    // ...
}

although you'd normally exclude the (- 1) and use less than instead of greater than. Knowing that, you should be able to convert this:

For i As Integer = myTable.Rows.Count - 1 To 0 Step -1
   '...
Next i

yourself, but in case you can't it's:

for (int i = myTable.Rows.Count - 1; i >= 0; i--)
{
    // ...
}

[Crash893]

so this is the correct syntax

for(starting count; condition to stop; howmuch to step by)

?

[jmcilhinney]

No. the syntax is:

for (initial action; condition to continue; action to take after each iteration)

This is a valid 'for' loop:

DateTime endTime = DateTime.Now.AddSeconds(20);

for (MessageBox.Show("Begin loop");
     DateTime.Now < endTime;
     MessageBox.Show("End iteration"))
{
    
}

There's nothing inherent in the 'for' statement that requires a loop counter at all. Have you read the MSDN help topic for the C# 'for' statement? If not then why not?

[David Anton]

One thing you should be aware of (Crash893) is that in VB, the expression "table.Columns.Count - 1" gets evaluated exactly once.
In C#, the "condition to continue" gets evaluated on every iteration. In you example, it probably doesn't make a difference, but this is a common source of errors when people convert these loops from VB to C#.

[Crash893]

thanks for the info all

i am in the proccess of trying it now so ill let you know

thanks