java giving incorrect maths answers when given a line of (maths related) code

Question

i am trying to run this code in java

double health = ((level*level +10000) * (level/150)/6) +100;

and it always come out as 100 (or whatever the last number is) in this instance level = 1 but even replacing the variable level with the number 1 wont fix this. when done right the answer should equal approximately 110 . please help me fix this code so i can continue programming

i have already tried breaking the line up into multiple separate lines of code, but still no fix. granted, this uses some pretty big fractions but it worked before and not all of a sudden it has stopped working. please help me to fix this problem,

thanks in advance.

Pritam Banerjee · Answer 1 · 2016-11-22T23:38:23.627

2

((level*level +10000) * (level/150)/6) get's floored off to the nearest number, which is 0.

So your code should be like this:

public static void main(String[] args) {

    double level = 10.0;

    double health = ((level*level +10000) * (level/150)/6) +100;

    System.out.println(health);
 }
}

edited Nov 22 '16 at 23:38

answered Nov 22 '16 at 23:16

Pritam Banerjee

17,953
10
93
108

1

It gets floored, not rounded. And you're completely wrong about float vs. double. – shmosel Nov 22 '16 at 23:17
@shmosel. Yeah, forgot the correct word. Changed it. Thanks – Pritam Banerjee Nov 22 '16 at 23:19
still not working – arcturus125 Nov 22 '16 at 23:20
@arcturus125 Try the code I provided – Pritam Banerjee Nov 22 '16 at 23:24
Can the mystery downvoter explain the downvote please? – Pritam Banerjee Nov 22 '16 at 23:32
The problem is with your level which is an int, so multiply with an int is getting as int, so you are loosing the fraction part, so try using level as double or {code} int level = 1; double health = ((double)(level*level) + 10000) * (((double)level)/150)/6 + 100; {code} – varra Nov 22 '16 at 23:36
@varra I am using `level` as `double` – Pritam Banerjee Nov 22 '16 at 23:37
@PritamBanerjee yeah, saw it, suppose if his business requirement doesn't allow him to change the level type to double, he can use explicit casting as I shown. – varra Nov 22 '16 at 23:39

score 1 · Answer 2 · answered Nov 22 '16 at 23:20

1

Assuming level is an int, level/150 will automatically get floored to a whole number, or 0. You can solve this by changing level to a float, or by changing 150 to 150f.

answered Nov 22 '16 at 23:20

shmosel

49,289
6
73
138

score 0 · Answer 3 · answered Nov 22 '16 at 23:26

0

fixed it. i needed to put (double) infront of the fraction

double health = ((1*1 +10000) * ((double)1/150)/6) +100;

without it the number is too small and the program must assumes it is 0

answered Nov 22 '16 at 23:26

arcturus125

11
1
2

java giving incorrect maths answers when given a line of (maths related) code

3 Answers3