Program wont run

[slider203]

This program reads in numbers from a file then calculate the the numbers cube (e.g. 4x4x4) The for loop should run from 1-25, since there are 25 pairs of values in the file.

Quote:

import java.io.*;
class FilesPrac2
{
public static void main (String args[])
throws java.io.IOException
{
FileReader fr = new FileReader ("squares.txt");
BufferedReader bfr = new BufferedReader (fr);
final int MAX = 25;
int product = 0;
int cube = 0;
int loopNum = 0;
int even_product = 0;
String input = "";
// This loop will output the even integers the squares
// and calculate and output the cubes of the even numbers.
for (int counter = 1 ; counter <= MAX;)
{
input = bfr.readLine();
loopNum = Integer.parseInt (input);
cube = (counter * counter * counter);
input = bfr.readLine();
even_product = Integer.parseInt (input);
System.out.print (counter + " " + product + " " + cube);
}
fr.close();
}
}

inside the squares.txt file:
0 0
2 4
4 16
6 36
8 64
10 100
12 144
14 196
16 256
18 324
20 400
22 484
24 576
26 676
28 784
30 900
32 1024
34 1156
36 1296
38 1444
40 1600
42 1764
44 1936
46 2116
48 2304
50 2500

I dont know why this prgram will not run I have tried everything I can think of but it still wont work any help is appreciated.

[Tony]

If there's an exception, it's typically printed out. What does it say? (Or in what other way does the program "not run"?)

[chrisbrown]

for (int counter = 1 ; counter <= MAX;)

I believe you want "counter++" after the semicolon?

[Tony]

That's not necessary; consider the

Java:

for (;;) {}

construct.

The program should still execute, although the logical error might produce an undesirable result.

[chrisbrown]

Good point Tony, forgot about that.

There are a couple of issues:

input = bfr.readLine();
readLine reads until a newline, so should be called only once per line. In your case, input would have the value "0 0", not "0". That isn't a parseable integer, so you will get an exception on this line: loopNum = Integer.parseInt (input);

After that is taken care of, you need to keep track of what line you're on or else you will read past the end of the file and the program will crash. See my other post for details.