C++ newbie help needed

[jpd727]

#include <iostream>
#include <cmath>
using namespace std;

// Stirling's Formula :::: e^(-n) * n^(n) sqrt(2)(PI)(n)
// n = 18

const int PI = 3.14;
double n;
double r;

int main()
{
int stirling1, stirling2;
cout << "Enter a number for n! : ";
cin >> n;
"Enter a number for r! : ";
cin >> r;
for (n; n > 1; n++)
{

stirling1 = n;
stirling2 = r * (n-r);

double CalcStirling = stirling1 / stirling2;

cout << "Stirling's string is : " << CalcStirling << endl;

return 0;
} }

All the syntax is good, it just doesnt do what I want to do.

Im trying to have n be 18 and calculate the factorial of that and r be 6 and have the factorial calculated. But it will not calculate. I type any # in for "n" and it shows it, but then you type in anything for "r" and it just returns 0.

Can anyone help me here so that it lets you input a value for both "n" and "r" and then returns the right result ?



Im VERYY new to C++ so please forgive me . Thanks

[GCDEF]

stirling1 and stirling2 are ints. Integer division truncates so you get 18 / 72 = 0.

[E-man96]

you need to turn stirling1 and stirling2 into float numbers, OR do a typecast
BTW: the curly brackets for the for loop is missing.

[richard_tominez]

PI should be a FLOATING POINT constant variable and shouldn't exist in your source code