Not getting correct volume of sphere

Question

this is my code

double inputrad = Convert.ToDouble(Console.ReadLine());
double circlevolume = 4/3 * Math.Pow(circlerad, 3) * Math.PI;

The volume of a circle with radius 2.5 is 65, but i am getting 49. Why?

use something like `4/3.0` otherwise you get integer division `4/3` which will give `1` — Pac0, Jul 03 '20 at 12:43
`double circlevolume = 4 * Math.PI / 3 * Math.Pow(circlerad, 3);` — Dmitry Bychenko, Jul 03 '20 at 12:46

Pac0 · Accepted Answer · 2020-07-03T15:38:27.907

You need to write something like 4/3.0 or 4.0/3 or 4/3d etc.. otherwise you are using integer division 4/3 which will give exactly 1.

You can also, as suggested by Dmitry Bychenko, change the order of operations to get a floating point result before applying division:

4 * Math.PI / 3 * Math.Pow(circlerad, 3).

The point is, integer divided by integer is integer division, and you absolutely need to avoid this.

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