Problem with Java code

[stamatiou]

Hey guys,
I have written a script in Java but I something is wrong....
The purpose of this program is to calcualate the average of your grades....

import java.util.Scanner;
class papi {
public static void main (String args[]){
Scanner input = new Scanner(System.in);
System.out.println("How many grades do you have?");
int grades = input.nextInt();
int total = 0;
int grade;
int average;
int counter = 0;
while (counter < grades){
System.out.println("Put your average number:");
grade = input.nextInt();
total = total + grade;
counter++;
}
average = total/grades;
System.out.println("Your average grade is " + average);
}

}

But when it is the time for the script to show the average it shows the last number....

[noneofthem]

Hello there!

I just tested your code on my machine and it works fine. I couldn´t find any obvious errors either. How do you use that script? As I said, in Eclipse (3.5.2) using Java 1.6.0.22) everything is alright here. There must be an error somewhere else.

[stamatiou]

Hello there!

I just tested your code on my machine and it works fine. I couldn´t find any obvious errors either. How do you use that script? As I said, in Eclipse (3.5.2) using Java 1.6.0.22) everything is alright here. There must be an error somewhere else.
And it makes an average? In my computer it prints me the last number...

[GregBrannon]

Each number input is assigned to 'grade', but your last line which prints the result, prints 'average' which is the result of total/grades. It would be purely coincidental if the result printed is the same as the last number input.

Suggestions:
Use more descriptive variable names. This is a simple program in which it's easy to remember the purpose of the handful of variables, but in a program of several hundred lines and almost as many variables, it may be hard to remember the difference between variables named 'grade' and 'grades'.

Expressions like 'total = total + grade;' can be (are usually) written as 'total += grade;'

When the number of times a loop will execute is known, the 'for' loop is the more typical choice. As you've shown, a 'while' loop can always be constructed to replace a 'for' loop, but avoid it unless the assignment requires it.

[PaulM1985]

Another thing that you may wish to consider is that your average will always appear to be rounded down. This is because you are using integer division.

if you used:


double average = (double)total / (double) grades;


The current code would average grades 5 and 6 to be 5, whereas this would give you 5.5.

Paul

[forrestcupp]

It would be purely coincidental if the result printed is the same as the last number input.Right. The last number you entered just happened to be the same as the average.



if you used:


double average = (double)total / (double) grades;
If you did the double thing, you would avoid that coincidence.

[stamatiou]

Million thanks guys...):P:guitar: