algorithm - Java: Scanner reads integer, but doesn't use it in while/for loop -

my book i'm learning uses libary reading inputs can't me....

i can't see mistake is. algorithm:

1. read value of n
2. set value of 3
3. follow steps

iterate

while < 2*n         i+1         write 1/(2*i+1) console. 

my code:

import java.util.scanner;  public class aufgabe420 { public static void main (string[] args) { int i, n;       system.out.println("please enter number!");     scanner sc = new scanner(system.in);     n = sc.nextint();     system.out.println("n ="+n);     system.out.println("the while-loop starts!");     = 3;     while (i < 2*n){         += 1;         system.out.println(1/(2*i+1));     }          system.out.println("now for-loop");          (i = 3; < (2*n); i+=1) {         system.out.println(1/(2*i+1));     }       } } 

but trying it, results in: please enter number! 5

n =5 while-loop starts! 0 0 0 0 0 0 0

now for-loop 0 0 0 0 0 0 0

what's wrong code? help.

1/(2*i+1) result in 0 positive i, since 1 < (2*i+1) , int division can't result in fractions.

change

system.out.println(1/(2*i+1)); 

to

system.out.println(1.0/(2*i+1)); 

you want perform floating point division, not int division.