Can't display correct percentage value in poll

Question

I'm trying to display a percentage in a TextView with the following code:

int votedTotal_int = pollObject.getList("votedBy").size();
System.out.println("Total votes cast: " + Integer.toString(votedTotal_int));

int value1_int = pollObject.getList("value1Array").size();
double value1_pct = ((value1_int / votedTotal_int) * 100);
String value1_string = String.valueOf(value1_pct);
holder.value1.setText(value1_string + " %");
System.out.println(holder.value1.getText().toString() + " votes");

Given that value1_int is 1, and votedTotal_int is 4, shouldn't the print out read 25.0%? So why am I getting the following?

07-24 16:48:21.626 13321-13321/com.test.android I/System.out: Total votes cast: 4
07-24 16:48:21.626 13321-13321/com.test.android I/System.out: 0.0 % votes
07-24 16:48:21.626 13321-13321/com.test.android I/System.out: 0.0 % votes
07-24 16:48:21.626 13321-13321/com.test.android I/System.out: 0.0 % votes
07-24 16:48:21.626 13321-13321/com.test.android I/System.out: 0.0 % votes

Dividing two integers will use integer division (i.e. 3/4 == 0). One could do `value1_int * 100.0 / votedTotal_int` or such. — Joop Eggen, Jul 24 '17 at 23:52
see [Integer division](http://stackoverflow.com/questions/4685450/why-is-the-result-of-1-3-0) — Scary Wombat, Jul 25 '17 at 00:00

score 0 · Answer 1 · answered Jul 24 '17 at 23:58

0

double value1_pct = (((double)value1_int * 100) / (double)votedTotal_int);

answered Jul 24 '17 at 23:58

Gutyn

432
4
19

JRG · Accepted Answer · 2017-07-25T00:11:04.277

-1

Change the below ..

double value1_pct = ((value1_int / votedTotal_int) * 100);

to

double value = (((double)value1_int * 100) / ((double)votedTotal_int));

Sample Run with value1_int=1 and votedTotal_int=1000 or 10000 or 100000

07-24 17:09:13.904 3491-3491/? D/TEST: 0.1
07-24 17:09:30.688 3589-3589/? D/TEST: 0.01
07-24 17:09:45.366 3685-3685/? D/TEST: 0.001

edited Jul 25 '17 at 00:11

answered Jul 24 '17 at 23:57

JRG

3,677
3
17
32

try your code with these values `int value1_int = 1; int votedTotal_int = 1000;` – Scary Wombat Jul 25 '17 at 00:03
This should not be the accepted answer - it is wrong – Scary Wombat Jul 25 '17 at 00:06
Why? It works just fine. – Martin Erlic Jul 25 '17 at 00:07
You were lucky with your value - see my comment above - it will return an incorrect value of `0` – Scary Wombat Jul 25 '17 at 00:08
see either @JoopEggen comment above or the linked duplicate question – Scary Wombat Jul 25 '17 at 00:09
updated solution to have Scary Wombat needs also working. – JRG Jul 25 '17 at 00:12
Nobody has justified the change yet in writing so I just selected this one as the final answer, because it was provided first. – Martin Erlic Jul 25 '17 at 00:40
Dear down voter, why are you down voting when the solution is updated to handle situations which weren't handled before? – JRG Jul 25 '17 at 00:44
@santafebound && JRG - The comment made by JoopEggen `value1_int * 100.0 / votedTotal_int` is a lot nicer – Scary Wombat Jul 25 '17 at 06:49

Can't display correct percentage value in poll

2 Answers2