This is a C++ program to compute Combinations using Recurrence Relation for nCr.
Algorithms
Begin
function CalCombination():
Arguments: n, r.
Body of the function:
Calculate combination by using
the formula: n! / (r! * (n-r)!.
End
Example
#include<iostream>
using namespace std;
float CalCombination(float n, float r) {
int i;
if(r > 0)
return (n/r)*CalCombination(n-1,r-1);
else
return 1;
}
int main() {
float n, r;
int res;
cout<<"Enter the value of n: ";
cin>>n;
cout<<"Enter the value of r: ";
cin>>r;
res = CalCombination(n,r);
cout<<"\nThe number of possible combinations are: nCr = "<<res;
}
Output
Enter the value of n: 7
Enter the value of r: 6
The number of possible combinations are: nCr = 2