Extremely Basic Program - 1 Problem

Question

This was assigned to me in my introductory Java class:
Write a program that reads an unspecified number of integers, determines how many positive and negative values have been read, and computes the total and average of the input values, not counting zeros. Your program ends with the input 0. Display the average as a floating-point number.
Here is the program I have written:
import javax.swing.JOptionPane;
public class AverageHW{
public static void main(String[] args){
int total, i;
double a, total2, i2;
int num, neg, pos;
neg = 0;
pos = 0;
total = 0;
i = 0;
while(1>0)
String input;
input = JOptionPane.showInputDialog(null,
"Enter a number to be averaged.",
"Enter",
JOptionPane.QUESTION_MESSAGE);
num = Integer.parseInt(input);
total += num;
++i;
if (num<0)
     neg++;
if (num>0)
     pos++;
if (num==0)
break;
a = (double)total / (double)i;
System.out.println("The sum is " + total);
System.out.println("The average is obviously not " + a);    // Just a joke.. like my skills in Java
System.out.println("There are " + neg + " negative inputs." );
System.out.println("There are " + pos + " positive inputs.");
System.out.println("There are " + (i - 1) + " combined inputs.");
System.out.println("This is quite frustrating.");
}Getting a correct average is the only thing I'm lacking.
I might be missing something in the chapters I've studied that is keeping me from attaining a floating point average. My teacher also explained this to me before, and I forgot it. Tried searching all over the net and trying different things but to no avail. I know the answer must be extremely simple, but this seems to be the only thing holding me back, as you can see.
Also, this isn't the only reason I posted this. I'd like to get feedback on potentially alternative and more efficient methods of coding this program. I know I have different options as far as using alternative loops and such, but just some insight would be helpful.
Thank you!
EDIT I know i have some random useless crap variables thrown in there, but those are the leftovers of me messing around with getting that average (tried making all the variables in the average equation double variables).
Edited by: g_0_0_d4 on Dec 17, 2009 12:46 AM

Answer 1

After reading your post pbrock, I was able to realize my mistake. "i" does not actually read the total numbers correctly, which is why I put "There are " + (i-1) + " combined inputs." I realized this earlier, but it never really registered that it was the compilation error that was causing the average to calculate incorrectly.
New code:
import javax.swing.JOptionPane;
public class AverageHW{
public static void main(String[] args){
int total, i;
double a, total2, i2;
int num;
int neg, pos;
neg = 0;
pos = 0;
total = 0;
i = 0;
while(1>0)
String input;
input = JOptionPane.showInputDialog(null,
"Enter a number to be averaged.",
"Enter",
JOptionPane.QUESTION_MESSAGE);
num = Integer.parseInt(input);
total += num;
i++;
if (num<0)
     neg++;
if (num>0)
     pos++;
if (num==0)
break;
i = (i-1);
a = (double)total / (double)i;
System.out.println("The sum is " + total);
System.out.println("The average is " + a);
System.out.println("There are " + neg + " negative inputs." );
System.out.println("There are " + pos + " positive inputs.");
System.out.println("There are " + i + " combined inputs.");
System.out.println("SUCCESS!");
JOptionPane.showMessageDialog(null,
"You have averaged your numbers.",
"Exit",
JOptionPane.INFORMATION_MESSAGE);
}Just removed (i-1) from the System.out.println and set i = i-1, it feels so good to finally finish.
Mel, your help is greatly appreciated. I should have known to use a boolean expression to determine the positive and negative numbers, but it kind of slipped my mind while I was writing this. The program you wrote is a little too advanced for my understanding, but I copy it down and study it for the future.
Thanks everyone!