Thanks. though I think the problem should have been more clear on what difference was, it felt like a very unclear tip. I had to use more maths here then coding since i knew that the absolute value is the distance between a point and origo.
I've created a program for something called eudoxus recursive series which is like this:
http://mathbin.net/56527
and this is the code
Code:
import javax.swing.*;
public class eudoxesseries {
public static void main(String[] arg) {
String k = JOptionPane.showInputDialog(null,"För vilket n?");
if (k == null)
System.exit(0);
long v = Long.parseLong(k);
long n = 0;
long an = 0;
long bn = 0;
long divison = 0;
long anneg1 = 1;
long bnneg1 = 1;
while (n < v ) {
an = anneg1 + bnneg1;
bn = an + anneg1;
bnneg1 = bn;
anneg1 = an;
n = n+1;
}
divison = bn/an;
JOptionPane.showMessageDialog(null, "För n = " + k + ": " + "\n" + "an= " + an + "\n" + "bn= " + bn + "\n"
+ "an/bn= " + divison);
System.exit(0);
}
}
however when I use long and when it calculates the divison it won't come out with decimals. i've tried putting divison = (double) bn/an;
but eclipse won't let me, it says cannot convert from double to long :S
So what do you guys think, Is the program fine or can i make changes to it to make it look cleaner?
But yeah primarily, how do i get division to work with long and can I improve the program in any way?
edit: about the swedish, it's only to type in for what n you wish the program to calculate for.
public class eudoxesseries {
public static void main(String[] arg) {
String k = JOptionPane.showInputDialog(null,"För vilket n?");
if (k == null)
System.exit(0);
long v = Long.parseLong(k); //kommer verka som gränsen för hur långt loopen skall gå.
long n = 0;
long an = 0;
long bn = 0;
double divison;
long anneg1 = 1; //startvärdet för an
long bnneg1 = 1; //startvärdet för bn
while (n < v ) {
an = anneg1 + bnneg1; //formeln an = an-1 + bn-1
bn = an + anneg1; // formeln bn = an + an-1
bnneg1 = bn; // görs om för att verka som bn-1 i nästa fall
anneg1 = an; // görs om för att verka som an-1 i nästa fall.
n = n+1; // räknare som håller reda på vilket n vi är på.
}
divison = (double) bn/an; // utför divisionen bn/an
JOptionPane.showMessageDialog(null, "För n = " + k + ": " + "\n" + "an= " + an + "\n" + "bn= " + bn + "\n"
+ "an/bn= " + divison); // skriver ut resultatet.
System.exit(0);
}
}
just made division as a double instead and since an and bn are of the type long i just put (division) infront. thus division = (double) bn/an;
But yeah, i wanna use long so an and bn don't come out as for example: 6.134535E18.
So yeah, been some time since I posted in this thread but I thought i'd ask what books you can recommend on learning java?
I've learned a bit now, like how to use loops, arrays, a bit about objects etc so I have a pretty much basic understanding of java. Now I feel like I need a good book and I have no idea which ones that are good. Any ideas?
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