Find highest,lowest and average in a loop

Question

I know it's probably something small that I'm doing wrong. I want it to print the lowest number etc. at the end of the loop, but it always prints zero as lowest. How do I get it to not put the exit mechanism zero as the lowest number.

Any advice please?

class HighLowAve
{
    public static void main (String[]args)
    {
        int num =0;
        int sum;
        int highest;
        int lowest;
        int index;
        Double average;

        highest = num;
        lowest = num;
        sum = 0;
        index = 0;

        do
        {
            System.out.println("Enter a number. Press zero to quit ");
            num = EasyIn.getInt();

            if (num > highest)
            {
                highest = num;
            }
            else if (num < lowest) 
            {
                lowest = num;
            }

            sum = sum + num;
            index++;
        }while (num !=0);

        average = (double) sum/(index-1);

        System.out.println("The highest number was " + highest);
        System.out.println("The lowest number was " + lowest);
        System.out.println("The average number was " + average);            
    }
}

Answer 1

Your highest and lowest variables both start at 0. So if your numbers are all negative, you'll get a highest of 0, incorrectly. If your numbers are all positive, you'll get a lowest of 0, incorrectly.

Just start off with highest = Integer.MIN_VALUE and lowest = Integer.MAX_VALUE and then the first iteration will end up with the correct highest and lowest value.

Answer 2

First check if the number is zero before changing the high and low values.

    do
    {
        System.out.println("Enter a number. Press zero to quit ");
        num = EasyIn.getInt();

        if (num == 0) break;

        if (num > highest)
        {
            highest = num;
        }
        else if (num < lowest) 
        {
            lowest = num;
        }

        sum = sum + num;
        index++;
    }while (num !=0);

Also you need to initialize highest and lowest before you do any comparisons on them in the loop.