Calculation the area of a triangle

Question

I'm using this code to calculate the area of a triangle, with the values 2, 2 and 1. When I do the calculation in my pocket calculator I get 0.97, but in C# it's 0. I guess it has something to do about the rounding of the decimals, but I have changed the last value from i and up, but still get 0 as the result! What am I doing wrong? Help preciated! Thanks!

double i = (valueA + valueB + valueC) / 2;
return Math.Round(Math.Sqrt(i * (i - valueA) * (i - valueB) * (i - valueC)),1);

Nikhil Agrawal · Accepted Answer · 2012-06-08T11:29:23.067

8

Divide by 2.0 or 2d or 2D

Reason: Integer Division gives only integer part and removes the fraction part.

2 is integer. 2.0 is double value.

double i = (valueA + valueB + valueC) / 2.0;

OR

double i = (valueA + valueB + valueC) / 2d;

OR

double i = (valueA + valueB + valueC) / 2D;

Second line remains the same

return Math.Round(Math.Sqrt(i * (i - valueA) * (i - valueB) * (i - valueC)),1);

edited Jun 08 '12 at 11:29

answered Jun 08 '12 at 11:24

Nikhil Agrawal

47,018
22
121
208

Or explicitly use the `D` suffix, e.g. `2D`. – Polynomial Jun 08 '12 at 11:25
Either are fine. I prefer 2D since it makes it more obvious as a suffix. – Polynomial Jun 08 '12 at 11:27
Thanks! Is the 'd' in 2d decimal? What are this letters called, I have seen al kinds of letters in combinations with numbers in code and I just want to learn more about it? – 3D-kreativ Jun 08 '12 at 11:29
Yes d in 2d is double. Sometimes we use `f` which means float. They are called Suffixes. – Nikhil Agrawal Jun 08 '12 at 11:30
@3D-kreativ They are termed [`Suffixes`](http://stackoverflow.com/questions/3271791/declaration-suffix-for-decimal-type/3271831#3271831) – V4Vendetta Jun 08 '12 at 11:32
Ok, but is there a common name for using this letters in combination of numbers? I would like to know if there a other usefull letters to use? – 3D-kreativ Jun 08 '12 at 11:32
@NikhilAgrawal for decimal its `m` and not `d` – V4Vendetta Jun 08 '12 at 11:34

score 2 · Answer 2 · answered Jun 08 '12 at 11:24

2

Please try (valueA + valueB + valueC) / 2.0.

answered Jun 08 '12 at 11:24

Jeffrey Zhao

4,923
4
30
52

Calculation the area of a triangle

2 Answers2