While-loop Restriction

Question

I want to restrict the while Loop.

I don't want to use break;, instead I want to say that the loop must end after three times.

My while Loop:

while(!file.isFile()) { userInput = JOptionPane.showInputDialog("UserInput);

score 4 · Answer 1 · answered Aug 15 '16 at 12:22

4

int i = 0;
while(!file.isFile() && i < 3) {
  userInput = JOptionPane.showInputDialog("UserInput);
  i++;
}

And I agree that for loop is better choice :)

answered Aug 15 '16 at 12:22

vbuhlev

509
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10

I quite like this way though; especially if you scope-block the whole thing. – Bathsheba Aug 15 '16 at 12:25
2

@Bathsheba it's effectively just an ugly way to declare a for loop, though. – Andy Turner Aug 15 '16 at 12:26
Indeed but this in many ways represents the simplest deviation to what the OP currently has. – Bathsheba Aug 15 '16 at 12:28

score 3 · Answer 2 · answered Aug 15 '16 at 12:22

3

Use a for loop instead :

for (int i = 0; i < 3 && !file.isFile(); i++) {
    userInput = JOptionPane.showInputDialog("UserInput");
    ...
}

answered Aug 15 '16 at 12:22

Eran

387,369
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haha i think you win for doing the logical thing and doing for and not just answering with while :P – natus Aug 15 '16 at 12:23
3

@natus I think that could be debated. Yes, using a for loop for counting is a more common practice; but putting "while" like conditions into a for loop on the other hand ... is not. I think many programmers that encounter a for loop like this might overlook the second condition. Thus, in my eyes, higher potential for running into bugs. Simply because people have different expectations when they see a while loop. – GhostCat Aug 15 '16 at 12:26
@GhostCat fair call :) – natus Aug 15 '16 at 12:27

GhostCat · Answer 3 · 2016-08-15T12:30:25.067

Then you need to make your while loop a for-loop like thing:

int counter = 0;

while (counter < 3 && !file.isFile()) { ...
  counter++;

For the record: the code you are showing isn't really useful: you are "overriding" the input you get from the user; and: you are condition !file.isFile() ... will not change its value ... because there is no code that would do that. In other words: there is more to fix about your code than just the way you are looping. It simply seems weird to ask the user the same thing three times; to ignore what he says the first two times.

score 3 · Answer 4 · answered Aug 15 '16 at 12:23

Consider refactoring to a for loop, introducing a counter variable in a tight scope:

for (int i = 0; i < 3 && !file.isFile(), ++i){
    userInput = JOptionPane.showInputDialog("UserInput"/*ToDo - quotation inserted*/);
}

The for loop conditional check i < 3 && !file.isFile() is verified before the statement in the loop body is ran.

score 0 · Answer 5 · answered Aug 15 '16 at 12:22

0

int i = 3;

while(!file.isFile() && i>0) { 
   userInput = JOptionPane.showInputDialog("UserInput");
   i--;
}

answered Aug 15 '16 at 12:22

ma3stro

313
2
11

score 0 · Answer 6 · edited Aug 15 '16 at 12:23

0

int count = 0;
while(!file.isFile() && count < 3 ) { 
   count++;
}

edited Aug 15 '16 at 12:23

brso05

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answered Aug 15 '16 at 12:22

natus

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score 0 · Answer 7 · answered Aug 15 '16 at 12:23

0

int counter = 0;
while(!file.isFile() && counter < 3) { 
   userInput = JOptionPane.showInputDialog("UserInput);
   counter++;
}

Replace 3 with the number of iterations you would like the loop to be limited to.

answered Aug 15 '16 at 12:23

Andy Dunnings

136
6

While-loop Restriction

7 Answers7