Permutation (C++)

Permutation

Permutation is an act of rearranging the values in an ordered fashion. For example, there are 6 permutations of the set {a,b,c}, namely [a,b,c], [a,c,b], [b,a,c], [b,c,a], [c,a,b], and [c,b,a].

Below is the code for calculating total number of permutations.

Code

#include "stdafx.h"

#include "iostream"

#include "conio.h"

using namespace std;

long GetFact(long number)

{

long factorial=1;

       for(int i=number;i>0;i--)

              factorial=factorial*i;

return factorial;

}

long nPr(int n,int r)

{

 return GetFact(n)/GetFact(n-r);

}

int main()

{

       cout<<nPr(5,0);cout<<endl;

       cout<<nPr(5,1);cout<<endl;

       cout<<nPr(5,2);cout<<endl;

       cout<<nPr(5,3);cout<<endl;

       cout<<nPr(5,4);cout<<endl;

       cout<<nPr(5,5);cout<<endl;

      

       _getche();

       return 0;

}

Output

1

5

20

60

120

120

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Combination (C++)