C++ Program to Compute Combinations using Factorials

The following is an example to compute combinations using factorials.

Example

 Live Demo

#include <iostream>
using namespace std;
int fact(int n) {
   if (n == 0 || n == 1)
   return 1;
   else
   return n * fact(n - 1);
}
int main() {
   int n, r, result;
   cout<<"Enter n : ";
   cin>>n;
   cout<<"\nEnter r : ";
   cin>>r;
   result = fact(n) / (fact(r) * fact(n-r));
   cout << "\nThe result : " << result;
   return 0;
}

Output

Enter n : 10
Enter r : 4
The result : 210

In the above program, the code is present in fact() function to calculate the factorial of numbers.

if (n == 0 || n == 1)
return 1;
else
return n * fact(n - 1);

In the main() function, two numbers of combination are entered by user. Variable ‘result’ is storing the calculated value of combination using factorial.

cout<<"Enter n : ";
cin>>n;
cout<<"\nEnter r : ";
cin>>r;
result = fact(n) / (fact(r) * fact(n-r));

Samual Sam

Updated on 26-Jun-2020 08:39:33

• Related Questions & Answers
• C++ Program to Compute Combinations using Recurrence Relation for nCr
• Using BigInt to calculate long factorials in JavaScript
• 8085 Program to compute LCM
• C++ Program to Compute Discrete Fourier Transform Using Naive Approach
• C program to compute geometric progression
• C program to compute linear regression
• C++ Program to Compute the Area of a Triangle Using Determinants
• Find last two digits of sum of N factorials using C++.
• Java program to compute Remainder and Quotient
• C++ Program to Compute DFT Coefficients Directly
• C Program to Compute Quotient and Remainder?
• Program to compute LCM in 8085 Microprocessor
• Program to compute Log n in C
• Python program to compute a Polynomial Equation
• Java Program to Compute Quotient and Remainder