Question

Time for my daily newbie Java question 😀

I must not be understanding conditionals in a while loop correctly.

I have this:

while (true){

     if (){
       ...
     } else {
       ...
     }
     if (){
       ...
     } else {
       ...
     }
     if (SENTINEL){
       break;
     }
 }

The first if/else statement is working, and the sentinel is working, but the second if statement gets skipped. If I flip the first and second if statement, then the first if statement still always gets executed and skips the second. What am I missing?

Can I have two if/else statements in one block like this?

I’ll include the whole code, though it’s pretty ugly, and I’m sure I’ll get lots of people telling me better ways of doing this. I don’t mind learning better ways, but for now, I just want an answer to this looping question. thanks!

public class FindRange extends ConsoleProgram {

    private static final int SENTINEL = 0;

    int value = 0;
    int highNumber = 0;
    int latestValue = 0;
    int lowNumber = 0;

    public void run() {         
        addNumbers();
    }

    private void addNumbers(){

        value = readInt("Enter number:");

        while(true){
            if (value == SENTINEL){
                break;
            }
            latestValue = readInt("Enter number:");
            getHighNumber();
            getLowNumber();         
            if (latestValue == SENTINEL){
                break;
            }
        }

        println("High Number is "+highNumber+".");
        println("Low Number is "+lowNumber+".");
    }

    private void getHighNumber(){
        if (latestValue >= value){
            highNumber = latestValue;
        }else {
            highNumber = value;
        }

    }
    private void getLowNumber(){
        if (latestValue <= value){
            lowNumber = latestValue;
        }else {
            lowNumber = value;
        }
    }
}

Answer 1

Are you trying to find the minimum and maximum of a series of numbers? If so, you should definitely use Math.min() and Math.max(). It’s much clearer that way and you can do away with the if statements. It’s also simple enough to do it in the loop with local variables instead of fields.

The common idiom is something like this:

minValue = Math.min(minValue, candidateValue);
maxValue = Math.max(maxValue, candidatevalue);