Recursion- DSA

By: Gulfam Tahir
Section : E2

                   Permutation Program through Recursive Call

#include<iostream>

using namespace std;

int punction(int,int);

int fac(int);

int fac(int n){

                if(n<=1){

                                return 1;           //base case

                }else{

                                return n*fac(n-1);     //recrssive case

                }

}

int punction(int k,int r){

                if(k<=1){

                                return 1;               //base case

                }

                else                          

                 {

                                return (k-r)*fac(k-r-1);     //recurssive case

                 }

}

int main(){

                cout<<"\n\n******************** Permutation *********************"<<endl;

                int n,r;

                                cout<<"\n\nEnter n"<<endl;

                cin>>n;

                cout<<"enter value of r"<<endl;

                cin>>r;

               

                int j=fac(n)/punction(n,r);

                cout<<"permutation of "<<n<<"P"<<r<<" "<<"is"<<" "<<j;

}