Program to Calculate Permutations and Combinations (nPr and nCr)

This is a C program to calculate number of permutations (nPr) and combinations (nCr) for given values of n and r. This program calculates nPr and nCr using functions.

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>

long double fact( int);
int ncr( int ,int);
long npr( int ,int);
main()
{
int n,r;
printf(" Enter value of n & r \n");
scanf("%d %d",&n ,&r);
if( n>= r)
{
printf( "%d C %d is %d \n",n,r,ncr( n ,r));
printf("%d P %d is %ld\n",n,r,npr( n, r));
}
else
{
printf("\n n should be greater than r");
getch ();
}



long double fact( int p)
{
long double facts = 1;
int i;
for( i = 1; i<= p; i++)
facts = facts * i;
return(facts);
}

int ncr ( int n, int r)
{
return( fact( n) / (fact( r) * fact(n- r) ) ) ;
}

long npr( int n ,int r)
{
return( fact( n) / fact( n- r));
}