Using an if statement and a int.tryparse to loop?

Question

I am trying to use an if statement and a int.tryparse to try and create a loop that keeps running until a proper integer is given. A friend of mine said it could be done using an the pieces I mentioned above. Yet I have my doubts, was wondering if anyone could either verify this works or help me figure it out.

so far I have

if (!int.TryParse(temp, out move)) 
{
    Console.WriteLine("Bad integer")
}

Looking at this I don't see how it would loop, I was thinking a while loop might work better but am at a loss as to how I would set one up.

Thanks in advance,

Jeff

what about this string temp = null; do{ if(temp != null)Console.WriteLine("Bad integer"); temp = Console.Readkey(); }while(int.TryParse(temp, out move); — Niranjan Singh
– Niranjan Singh, Commented Jan 22, 2015 at 6:40

paxdiablo · Accepted Answer · 2015-01-22 06:43:08Z

4

Unless that's within a loop of some sort, continuously asking for a new temp value, it won't loop back for more.

The sort of thing you're looking for is:

temp = Console.ReadLine();
while (!Int32.TryParse(temp, out move))  {
    Console.WriteLine("Bad integer");
    temp = Console.ReadLine();
}
// move should be okay now.

though there's a lot you can do to improve, handling exceptions and so on.

edited Jan 22, 2015 at 6:43

answered Jan 22, 2015 at 6:37

paxdiablo

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2 Comments

Jeff Over a year ago

Just for clarification, the while(!int.TryParse(temp, out move)) means that while int.TryParse fails (or returns false/null?), keep looping through?

paxdiablo Over a year ago

@Jeff, yes. TryParse returns true if all is okay, so false means something went wrong. Using ! will invert that return value. In English, while didn't fail parsing.

JunaidKirkire · Accepted Answer · 2015-01-22 06:41:31Z

0

@Jeff Simply using the int.TryParse won't make a loop. You will have to write it in a while loop as below -

while( //your condition)
{
  if (!int.TryParse(temp, out move)) 
  {
    Console.WriteLine("Bad integer")
  }
}

answered Jan 22, 2015 at 6:41

JunaidKirkire

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Comments

JConstantine · Accepted Answer · 2015-01-22 06:42:41Z

0

int move;

Console.Write("Enter int: ");
var temp = Console.ReadLine();

while (!int.TryParse(temp, out move))
{
    Console.Write("Enter int: ");
    temp = Console.ReadLine();
}

answered Jan 22, 2015 at 6:42

JConstantine

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Comments

Amit · Accepted Answer · 2015-01-22 06:43:59Z

0

Try this -

    int j;
    while (!int.TryParse(Console.ReadLine(),out j))
    {
        Console.Write("Bad integer\n");
    }

answered Jan 22, 2015 at 6:43

Amit

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Comments

user3161402 · Accepted Answer · 2015-01-22 06:45:23Z

0

int corectinteger;
int input = Console.ReadLine();
bool flag = true;
while (flag)
{
    if (input != corectinteger)
    {
        Console.WriteLine("Bad integer");
        input = Console.ReadLine();
    }
    else if (input == corectinteger)
        flag = false;
}

answered Jan 22, 2015 at 6:45

user3161402

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