Problem showing a number

Question

string temp;
temp = textBox1.Text.ToString();

double temp2;
temp2 = Convert.ToDouble(temp);
double fhar=(temp2/(5/9))+32;
string fhr = fhar.ToString();
MessageBox.Show(fhr);

Messagebox shows 0 or infinity, depending on what gets in.

Thanks to whoever answer.

Eamonn · Answer

Feel free to tag it as accepted :-)

Rafael Anschau · Answer

Eamonn, you are an Angel, thank you so much.

Eamonn · Answer

double fhar=(temp2/( 5/9 ))+32; This is where the problem is, 5 & 9 are Int32 literals. Int32/Int32 produces and Int32, so dividing a large Int32 by a smaller Int32 will always produce 0. Dividing any number by zero will produce a Divide By Zero problem which is why you are getting infinity. So why are you not getting a DivideByZero exception? Well if you were assigning the result to an Int32 then you would get a DivideByZero exception, actually yuo woudl get a compiler error as it woudl evaluate 5/9 as a literal zero. However, when assigning the result to a double or any floating point type, it will not throw an exception and will simply give you an infinity result. I'm not a mathematician but there is probably a good mathematical reason for this behaviour. You can easily correct this by casting 5 & 9 up to a floating point: double fhar=(temp2/( (double)5/(double)9 ))+32; Ideally though, you should assign 5 & 9 to a floating point constant. e.g. double const five = 5.00; double double const nine = 9.00 double fhar=(temp2/( five/nine ))+32;