Add up numbers in a for loop

Question

I got a very simple problem that I cant figure out.

This is what i want to do :

6 * (1/(1*1) + 1/(2*2) + 1/(3*3) + … + 1/(N*N))

And this is my code attempt, that does not work.

int eingabe = 5;
double c = 0;

    for (int i = 1 ; i<=eingabe ;i++) {
         c += 1/(i*i);
    }
    c *= 6;
    System.out.println(c);

Please help me guys ! What do I have to do to make the code work?

I know @rtruszk - that's why it was a comment and not an answer — Ross Drew, Nov 04 '14 at 09:10

score 7 · Accepted Answer · answered Nov 03 '14 at 14:58

7

change 1/(i*i) to 1.0/(i*i), currently you're doing integer division

answered Nov 03 '14 at 14:58

yurib

score 2 · Answer 2 · answered Nov 03 '14 at 14:59

2

int eingabe = 5;
double c = 0;

for (int i = 1 ; i<=eingabe ;i++) {
     c += 1.0/(double)(i*i);
}
c *= 6;
System.out.println(c);

answered Nov 03 '14 at 14:59

i.krivosheev

1

casting to (double) is not needed here. When you divide double number by integer number then integer will be automatically converted to double – rtruszk Nov 03 '14 at 15:01
1

and you don't need 1.0 . 1 is sufficient if u cast – Madhawa Priyashantha Nov 03 '14 at 15:02

2 Answers2