Anyone know C++?

[Nicko01]

Hello. I was bored and decided to make a program for windows to calculate pi, but its not working...


ok, heres what i wrote:

#include <iostream>
int main()
{
using namespace std;
long double pi;
unsigned long int denom;
bool subtract;
denom = 1;
subtract = true;
pi = 4;
while(true)
{
           cout << pi;
           cout << "\n";
           if (subtract == true)
           {
              denom = denom + 2;
              pi = pi-4/denom;
              subtract = false;
           }
           else
           {
              denom = denom + 2;
              pi = pi+4/denom;
              subtract = true;     
           }
           
}

return 0;
}

it just prints out 3 repeatedly!
it seems like it's rounding off everything. Is there any way I can stop this from happening and can anyone tell me WHY this is happening?

I dont really need it for calculating pi, i have around 90 digits memorized
I just need to work on my programming skills....
thats the whole reason for this program.
(please dont just read this and then hit the back button without saying something)

[gdf]

i don't know.
check it against tuts here- http://www.cprogramming.com/tutorial.html

[VampDude]

I know some C++, but not enough to actually help anyone...

...Oh and your code is horrible!

[quzar]

make both pi and denom an unsigned long double, or just add a .0 to the end of the 4. The problem is that it's getting turned back into an int because it thinks it doesn't need the precision.