How to make a program that lies one-third of the time?

Question

I am supposed to take this code (that I made):

public void showUpdatedStatus()
{
    if(((itsUsersNumber - itsSecretNumber) <= 2) && ((itsUsersNumber - itsSecretNumber) >= -2))
        JOptionPane.showMessageDialog(null, "You're hot!");
    if (((itsUsersNumber - itsSecretNumber) <= 6) && ((itsUsersNumber - itsSecretNumber) >= -6))
        JOptionPane.showMessageDialog(null, "You're warm.");
    if ((itsUsersNumber - itsSecretNumber) < -6)
        JOptionPane.showMessageDialog(null, "Too low.");
    if ((itsUsersNumber - itsSecretNumber) > 6)
        JOptionPane.showMessageDialog(null, "Too high.");
}

And change it so it does this:

Have the program lie one-third of the time that the guess is too high; it says it is too low. But it never lies about the guess being too low, nor does it lie twice in a row.

I believe I have managed to do this with this method for checking whether the guess is "too high."

public void TooHigh()
{
    int numLies = 1;
    if ((itsUsersNumber - itsSecretNumber) > 6)
    {
        itsLieNum = randy.nextInt(2);
        if(itsLieNum == 1 && numLies == 1){
            numLies = 2;
            JOptionPane.showMessageDialog(null, "Too low.");}
        else
            numLies = 1;
            JOptionPane.showMessageDialog(null, "Too high.");
    }
}

I just want to know whether or not it seems like it would work fine. I would just test it, but it would probably take me quite a while to make sure that it not only works 1/3 of the time, but also that it doesn't do it twice in a row.

EDIT: I managed to get everything working fine with this code:

public void showUpdatedStatus()
{

    if(((itsUsersNumber - itsSecretNumber) <= 2) && ((itsUsersNumber -itsSecretNumber) >= -2))
        JOptionPane.showMessageDialog(null, "You're hot!");
    else if (((itsUsersNumber - itsSecretNumber) <= 6) && ((itsUsersNumber -itsSecretNumber) >= -6))
        JOptionPane.showMessageDialog(null, "You're warm.");
    if ((itsUsersNumber - itsSecretNumber) < -6)
        JOptionPane.showMessageDialog(null, "Too low.");
    else 
        TooHigh();
}

public void TooHigh()
{
    if ((itsUsersNumber - itsSecretNumber) > 6)
    {
        itsLieNum = randy.nextInt(3);
        if(canLie && itsLieNum == 1){
            canLie = false;
            JOptionPane.showMessageDialog(null, "Too low.");}
        else{
            canLie = true;
            JOptionPane.showMessageDialog(null, "Too high.");}
    }
}

Thanks to rolfl

Answer 1

The concept you have going is 'OK' (cumbersome, but for a beginner it's OK). There are two bugs, and one recommendation that will help a lot.

First the recommendation....

Change numLies to be a boolean value like: boolean canlie = true;

Then, your code becomes:

if(canlie && itsLieNum == 1){
    canlie = false;
    ....
} else {
    canlie = true;

This makes the purpose of the code more apparent. Also, a bug is that you have to declare this ourside your method. It should be a class-variable, not a method variable, otherwise it will always be the wrong value.

The bug you have is a technical one (but important that you learn) ... Random.nextInt(value) will never return the input value. It will retrun 0(inclusive) to value(exclusive). In your case, with nextInt(2) it will only ever return 0, or 1. Change that to be nextInt(3) and you will get the values 0, 1, or 2 and it will be 1 1 third of the time.

Answer 2

I'll review your Rev 4, though some of these remarks also apply to the original code. Note that all of these criticisms are on style rather than correctness. The correctness of your code is pretty good starting with Rev 4.

• You use (itsUsersNumber - itsSecretNumber) many times. For brevity, readability, and maybe performance, define int diff = itsUsersNumber - itsSecretNumber.
• I suggest chaining your conditions as if … else if … else if … else, to emphasize that the code branches are all mutually exclusive, and that one of them must always be true.

• I strongly recommend writing the braces, and placing them according to the official Java style guide (§ 7.4):

  int diff = itsUsersNumber - itsSecretNumber;
  if (-2 <= diff && diff <= 2) {
      …
  } else if (-6 <= diff && diff <= 6) {
      …
  } else if (diff < -6) {
      …
  } else {
      assert diff > 6;
      …
  }
  

  Your placement of braces in TooHigh() is weird and confusing.

• I would change public void TooHigh() to private void handleTooHigh(). It's a helper function, not to be called by code in any other class, so access should be private. Method names should start follow the lowerCase capitalization convention.
• I would expect that TooHigh() would only ever be called when a number is too high. Therefore, TooHigh() shouldn't have to bother checking that the guess is too high.
• In TooHigh(), itsLieNum should be local, if you need to have a variable at all.