Im looping a question untill the user puts in the value i want to accept. In this case its a number with a dash and it should be 7 'symbols' long.
My problem is putting the ReadLine inside of the while() statement.
So this is my code:
string cpr = "";
do
{
cpr = Console.ReadLine(); //I dont want ReadLine here :/
} while (
//I want Console.ReadLine() here
cpr.Length != 7
&&
!Regex.IsMatch(cpr, #"^[0-9-]+$")
&&
Regex.IsMatch(cpr, #"^[a-z]+$")
);
Putting ReadLine in a while statement is possible i have some other code that works while try parsing an int
do
{
//do something here
} while (!int.TryParse(Console.ReadLine(), out int1));
Try something like this:
string cpr = "";
bool condition = true;
while (condition )
{
cpr = Console.ReadLine();
if(cpr is ok)
{
condition = false;
}
}
While I agree with the comments (in that this isn't the best way to approach this - in fact, the code you've provided is more than adequate), you can do assignment inside of a conditional statement. ie.
var str = "";
do
{
...
} while ((str = Console.ReadLine()).Length != 7 && Regex.IsMatch(str, ...));
Except in this case, you'd need to use a while loop, instead of a do-while (since you won't capture input until the end of the loop with the do-while pattern).
Related
So I need to count lines in a textbox, to do this i use:
if (subject.Length <= 20)
{
bool moreLines = true;
int onLine = 2;
int count = 0;
while (moreLines)
{
textBody[count] = TextBox_Text.Text.Split('\n')[onLine];
Console.WriteLine("Line saved: " + textBody[count]);
onLine++;
count++;
try
{
if (TextBox_Text.Text.Split('\n')[onLine] == null)
{
}
}
catch (IndexOutOfRangeException)
{
moreLines = false;
}
}
return true;
}
I insert the split strings into textBody[] array but once I approach the last lines where there is no text I want the loop to stop. I tried to do an if statement which checks if the next line is null, and if yes stop the loop. However, I kept getting an IndexOutOfRangeException so I just put the whole thing in a try catch, but I feel like there would be an easier way to do this?
I think you might have over complicated things massively.
The String.Split method have multiple overloads, some of them takes as an argument a member of the StringSplitOptions enum - one of it's members is called None, and the other is called RemoveEmptyEntries - so as far as I understand, all you need is this:
var textBody = TextBox_Text.Text.Split(
new char[] {'\n'},
StringSplitOptions.RemoveEmptyEntries);
An easy way to do this would just to use the following:
TextBox_Text.Text.Split('\n').Length
The Length property returns the length of the array.
so I just used the LineCount property instead and done a compare to the onLine
if (TextBox_Text.LineCount >= onLine)
{
moreLines = false;
}
Hi guys how can you repeat one iteration in a foreach?
foreach (string line in File.ReadLines("file.txt"))
{
// now line == "account", next line == "account1"
if (line.Contains("a"))
//next loop take "account1";
else
// need to set that next loop will take line == "account" again
}
How to do it?
While I don't fully understand your example, I think I understand your question. I had the same problem and was able to come up with a solution: include a while loop within the foreach. In your example it would look like this:
foreach (string line in File.ReadLines("file.txt"))
{
bool repeat = true;
while (repeat)
{
// now line == "account", next line == "account1"
if (line.Contains("a"))
{
//do your logic for a break-out case
repeat = false;
}
else
{
//do your logic for a repeat case on the same foreach element
//in this instance you'll need to add an "a" to the line at some point, to avoid an infinite loop.
}
}
}
I know I'm very late to the game, but hopefully this will be helpful for anyone else who stumbles in here with the same problem.
There is no need to change your code, assuming it only has an if/else construct in the loop.
When the if condition evaluates to true the else will not execute and the loop resumes.
In a more complex where you want to immediately resume the loop and ensure nothing else following the condition executes, use the continue statement:
The continue statement passes control to the next iteration of the enclosing while, do, for, or foreach statement in which it appears.
foreach (string line in File.ReadLines("file.txt"))
{
// now line == "account", next line == "account1"
if (line.Contains("a"))
continue;
else
// need to set that next loop will take line == "account" again
// more stuff that we don't want to execute if line.Contains("a")
}
I guess this might also helpful if someone else come
for (int i = 0; i < inventoryTimeBlocks.Count; i++)
{
if (line.Contains("a"))
//next loop take "account1";
else
{
if(i > 0)
{
i = i - 1;
continue;
}
}
}
I have a While loop that reads a line of a file.txt. I also have a method named VerifyPhoto that returns true/false I want to go to next item of the while loop if the returned value is false. How Could I do that ? I tried break and return but it just leave all and back to the form...
while (!reader.EndOfStream)
{
if(VerifyPhoto(filed.matriculation) == false)
{
//go to the next line of the file.txt
}
}
You may want to get familiar with other control statement: continue
[EDIT] Newest version of the doc: continue, thanks Jeppe.
continue; (some more to make it 30 chars)
Depending on your actual code, maybe you could simply invert the boolean test, so you do something only if VerifyPhoto returns true:
while (...)
{
if(VerifyPhoto(filed.matriculation))
{
// Do the job
}
}
The continue statement passes control to the next iteration of the enclosing iteration statement in which it appears
while (!reader.EndOfStream)
{
if(VerifyPhoto(filed.matriculation) == false)
{
continue;
//go to the next line of the file.txt
}
}
Am I missing something in the way you are doing this?
Do you read the first line before starting the loop?
if so don't you need something like
**string line;**
while (!reader.EndOfStream)
{
if(VerifyPhoto(filed.matriculation) == false)
{
//go to the next line of the file.txt
**line = file.ReadLine();**
}
}
If you're trying to read line by line then File.ReadLines may be useful.
Also what you're looking for is the continue statement.
string myFile = #"c:\path\to\my\file.txt";
foreach(string line in File.ReadLines(myFile))
{
//Do stuff
//if(!VerifyPhoto())
// continue;
//Do other logic
}
I know this is a very newbie C# question but I am implementing a small program which does the following:
namespace ConsoleApplication
{
class Program
{
static void Main(string[] args)
{
bool isRun = false;
int number = 0;
while (isRun = (true) && number < 3)
{
++number;
Console.WriteLine("Number = {0}", number.ToString());
Console.WriteLine();
}
Console.WriteLine(isRun.ToString());
Console.ReadLine();
}
}
}
At the end of the while loop, I would have expected the bool value to be true, but is is printed to be false. Why is that? Is this different from C++ where I would have done something like and the same thing in C# is giving me false
while(number<3)
{
is = true;
}
if(is){
cout<<true;
}
The reason you're seeing this behavior is due to the operator precedence involved. Here the && binds more strongly than = so the code in the loop is actually bound as the following
while (isRun = (true && number < 3)) {
...
}
Once number > 3 the && expression is false and is assigned into the isRun value and simultaneously terminates the loop. Hence once the loop exits you will see isRun as false
To get the behavior you are looking for you will need to manually correct the precedence with parens.
while ((isRun = (true)) && number < 3) {
...
}
Note: In general, as #Servey pointed out, the assignment of locals to expressions inside the loop predicate is considered bad practice. Many C# users would actually be surprised that code compiles at all because they've been conditioned to only use == in loops.
It's more idiomatic to simply set isRun to true on the first line of the loop for this pattern.
while (number < 3) {
isRun = true;
...
}
The problem is that you have set you boolean variable to false and without assigning it back to true, in while loop you are matching it against the value true, thus it fails in every case.
This question already has answers here:
Closed 11 years ago.
Possible Duplicates:
Breaking out of a nested loop
How to break out of 2 loops without a flag variable in C#?
Hello I have a function that has nested loops. Once the condition has been met, I want to break out of nested loops. The code is something like this below:
foreach (EmpowerTaxView taxView in taxViews)
{
foreach (PayrollEmployee payrollEmployee in payrollEmployees)
{
//PayStub payStub = payrollEmployee.InternalPayStub;
IReadOnlyList<PayrollWorkLocation> payrollWorkLocations = payrollEmployee.PayrollWorkLocations;
foreach (PayrollWorkLocation payrollWorkLocation in payrollWorkLocations)
{
Tax tax = GetTaxEntity(payrollWorkLocation, taxView.BSITypeCode, taxView.BSIAuthorityCode,
paidbyEr, resCode);
if (tax != null && tax.Rate.HasValue)
{
taxRate = tax.Rate.Value;
break;
}
}
}
}
Unfortunately, break comes out of only one loop. I want to break out of the whole thing. Please, I know some people have suggested goto: statement. I am wondering is there any other way around, such writing some LINQ queries to the same effect.
Any ideas and suggestions are greatly appreciated !
Two options suggest themselves as ways of getting out without having an extra flag variable to indicate "you should break out of the inner loop too". (I really dislike having such variables, personally.
One option is to pull all of this code into a separate method - then you can just return from the method. This would probably improve your code readability anyway - this really feels like it's doing enough to warrant extracting into a separate method.
The other obvious option is to use LINQ. Here's an example which I think would work:
var taxRate = (from taxView in taxViews
from employee in payrollEmployees
from location in employee.PayrollWorkLocations
let tax = GetTaxEntity(location, taxView.BSITypeCode,
taxView.BSIAuthorityCode,
paidbyEr, resCode)
where tax != null && tax.Rate.HasValue
select tax.Rate).FirstOrDefault();
That looks considerably cleaner than lots of foreach loops to me.
Note that I haven't selected tax.Rate.Value - just tax.Rate. That means the result will be a "null" decimal? (or whatever type tax.Rate is) if no matching rates are found, or the rate otherwise. So you'd then have:
if (taxRate != null)
{
// Use taxRate.Value here
}
Well, you could use the dreaded goto, refactor your code, or this:
// anon-method
Action work = delegate
{
for (int x = 0; x < 100; x++)
{
for (int y = 0; y < 100; y++)
{
return; // exits anon-method
}
}
};
work(); // execute anon-method
You could use a flag variable.
bool doMainBreak = false;
foreach (EmpowerTaxView taxView in taxViews)
{
if (doMainBreak) break;
foreach (PayrollEmployee payrollEmployee in payrollEmployees)
{
if (doMainBreak) break;
//PayStub payStub = payrollEmployee.InternalPayStub;
IReadOnlyList<PayrollWorkLocation> payrollWorkLocations = payrollEmployee.PayrollWorkLocations;
foreach (PayrollWorkLocation payrollWorkLocation in payrollWorkLocations)
{
Tax tax = GetTaxEntity(payrollWorkLocation, taxView.BSITypeCode, taxView.BSIAuthorityCode,
paidbyEr, resCode);
if (tax != null && tax.Rate.HasValue)
{
taxRate = tax.Rate.Value;
doMainBreak = true;
break;
}
}
}
}