What it looks like:
The code was all the same except that instead of printing the hard-coded string "Right" if the user got the answer right, it printed answerAffirmation. This was a method that generated one of 4 random integers and mapped each integer to a different congrats message.
if (userAnswer == programSolution) {
println(answerAffirmation());
}
else {
println("No, the correct answer is " + programSolution);
}
I used a switch statement. At first the method was buggy because the program thought I wasn't returning a result:
The problem was, even though having the strings map to one of four integers that I knew would be exhaustive, the program didn't realize that answers could only come from that random integer, so I must include a default string to get returned:
Ah, this problem with switch statements actually shows up in the textbook, for an example method for the "Stoplight" class called getState();
ReplyDelete/**
* Returns the current state of the stoplight.
* @return The state of the stoplight (GREEN, YELLOW, or RED)
*/
public Color getState() {
switch (state) {
case 0: return GREEN;
case 1: return YELLOW;
case 2: return RED;
default: return null; /* Can't occur but required by Java */
}
}
You could also consider defining a list of affirmations and then picking one randomly, for e.g.:
ReplyDelete// In your constructor
this.affirmations = new ArrayList();
this.affirmations.add("That's it!");
this.affirmations.add("Hi five, that's the correct answer!");
// ...
Then you can rewrite like so:
public String randomlyChoose(List elements) {
int index = rgen.nextInt(0, elements.size() - 1);
return elements.get(index);
}
// ...
if (userAnswer == programSolution) {
println(randomlyChoose(this.affirmations));
}
else {
println("No, the correct answer is " + programSolution);
}
Why might this be preferred? Here are some reasons, some disputable some not:
- Avoids the unnecessary use of default in the switch
- Separates your data (i.e. possible affirmations) from business logic (i.e. how to choose affirmations)
- Creates a general method for randomly choosing from a list of String objects, might be useful later
- Possible that testing randomlyChoose() is easier than testing answerAffirmation()
Or even just an Array literal instead of a case statement. That'd be groovy too.
ReplyDelete