Java: Re-running user input in program after invalid entry (loop?)

Question

After making an invalid entry, the invalid entry loop continues to appear in this program. I am seeking to keep asking the user for input until he/she enters valid data. Then I'd like to use that input to continue on with the program. I'm positive there's a type of loop associated with this. Thanks for your help.

identInput = JOptionPane.showInputDialog(null, "Please enter a student ID: ");
intID = Integer.parseInt(identInput);
savedIntID = Integer.parseInt(identInput);

for(x = 0; x < studentIDs.length; ++x)
{
    if(identInput.equals(studentIDs[x]))
    {
        JOptionPane.showMessageDialog(null, "The first name associated with \nStudent ID "
                + intID + " is: " + firstNames[x] + "\n" + firstNames[x] + "'s current GPA is: "
                + gPAs[x]);

        inputTruth = true;
        break;
    }
}

//The following will show up and continue to if the data is incorrect. Am not
//sure how to reuse if good data are entered.

while(inputTruth == false)
{
    JOptionPane.showInputDialog(null, "The Student ID you entered "
            + savedIntID + "\nis not valid. \nPlease enter another Student ID: ");
}

Andreas L. · Accepted Answer · 2014-04-24 07:06:46Z

1

inputTruth = false;
while(inputTruth == false)
{
identInput = JOptionPane.showInputDialog(null, "Please enter a student ID: ");
intID = Integer.parseInt(identInput);
savedIntID = Integer.parseInt(identInput);

for(x = 0; x < studentIDs.length; ++x)
{
    if(identInput.equals(studentIDs[x]))
    {
        JOptionPane.showMessageDialog(null, "The first name associated with \nStudent ID "
                + intID + " is: " + firstNames[x] + "\n" + firstNames[x] + "'s current GPA is: "
                + gPAs[x]);

        inputTruth = true;
        break;
    }
}

//The following will show up and continue to if the data is incorrect. Am not
//sure how to reuse if good data are entered.

if(inputTruth == false)
{
    JOptionPane.showInputDialog(null, "The Student ID you entered "
            + savedIntID + "\nis not valid. \nPlease enter another Student ID: ");
}
}

answered Apr 24, 2014 at 7:06

Andreas L.

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2 Comments

ewbrowning Over a year ago

Thank you, although same as the comment above, the program continues to ask for valid inputs even after correct data is entered. Any ideas on how to reuse data?

Andreas L. Over a year ago

If you it does not work with correct data, the problem is in if(identInput.equals(studentIDs[x])). Try to log what is there with System.out.println(...) and also log the stundentIDs[x].

Sarz · Accepted Answer · 2014-04-24 07:05:04Z

1

You just Need a while loop

while(!isInputValid){
 //Take your input
 if(check == input){
   isInputValid = true;
 }else{
  //Please enter valid input try again.
 }
}

answered Apr 24, 2014 at 7:05

Sarz

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Comments

richard · Accepted Answer · 2014-04-24 07:23:23Z

1

is this what you want ?

inputTruth = false;

while(inputTruth == false)
{
  for(x = 0; x < studentIDs.length; ++x)
  {     
    if(identInput.equals(studentIDs[x]))
    {
     JOptionPane.showMessageDialog(null, "The first name associated with \nStudent ID "
       + intID + " is: " + firstNames[x] + "\n" + firstNames[x] + "'s current GPA is: " 
       + gPAs[x]);

     inputTruth = true;
     break;
   }
 }
 if (inputTruth == false) {
 identInput = JOptionPane.showInputDialog(null, "The Student ID you entered " 
  + savedIntID + "\nis not valid. \nPlease enter another Student ID: ");
  }
}

edited Apr 24, 2014 at 7:23

answered Apr 24, 2014 at 7:07

richard

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3 Comments

ewbrowning Over a year ago

sort of, this works, but after the program recognizes the incorrect data, it just continues to ask... regardless if correct data is entered thereafter. I appreciate your help though!

richard Over a year ago

my mistake, would you please try this one? feel free to tell me if it doesn't work

ewbrowning Over a year ago

No worries, your help is appreciated. What needed to happen is to start the while loop before the user make his/her input. Thanks again!

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