Convert a string in a label to int not working properly

Question

I have the following code:

int a = Int32.Parse(weight.Text);
double b = 0;

if (this.wcf.SelectedItem == weighing)
{
    b = (a * 1.03) / 1000;
    wll.Content = b.ToString();
}

weight is the name of a TextBox and in this TextBox where the input is made which is 50000. wll is a Label where the calculation of b is shown. wll shows 51.5 which is correct.

I want to use the value of b in a calculation further down and therefore I have defined a new int:

int p = Convert.ToInt32(b);
double g = 0;          

double sq = Math.Sqrt(50 / p);

The value of sq should then be 0,985 and is shown in the label daf, but the program shows 1,492. Something is not correct here, can anyone help me?

g = (1.09 + (0.41 * sq));
daf.Content = g.ToString();

Answer 1

Beware of this:

int p = Convert.ToInt32(b);
double g = 0;          
double sq = Math.Sqrt(50 / p); //int/int

this will make you have Math.Sqrt(int), losing precision. Instead, you should do:

double sq = Math.Sqrt(50D / p); //double/int

or

double sq = Math.Sqrt((double)50 / p); //double/int

or

double sq = Math.Sqrt(50.0 / p); //double/int

Declare 50 as double

In addition, since your b can have result of non-integer, you may want to change this line too:

int p = Convert.ToInt32(b); //same issue losing precision

into

double p = Convert.ToDouble(b); //use double instead