binBin

// bin&Bin Calculator
// Jean-Marc Saad
#include <iostream>
#include <cmath>
#include <string>
using namespace std;
int factorial(int n);
double Combination(int,int);
double bin(int,int,double);
double Bin(int,int,double);
int main()
{
    int x,y;
    double z;
    int io;
    cout << " 0 for bin, 1 for Bin " << endl;
    cin >> io;
    if (io == 0)
    cout << " b(a,b,c) " << endl;
    else
    cout << " B(a,b,c) " << endl;
    cout << "a = ";
    cin >> x;
    cout << "b = ";
    cin >> y;
    cout << "c = ";
    cin >> z;
    if (io == 0)
    cout << bin(x,y,z);
    else
    cout << Bin(x,y,z);

    return 0;
}
int factorial(int n)
{
    if (n == 0)
       return 1;
    return n * factorial(n - 1);
}
double Combination(int a, int b)
{
    return (factorial(a))/((factorial(b))*(factorial(a-b)));
}
double bin(int a,int b,double x)
{
    return (Combination(b,a))*pow(x,a)*pow(1-x,b-a);
}
double Bin(int a, int b, double x)
{
    double sum = 0;
    for (int i=0;i<=a;i++)
    {
        sum += bin(i,b,x);
    }
    return sum;
}