nCr과 nPr을 찾는 C 프로그램

result = factorial(n)/(factorial(r)*factorial(n-r));

result = factorial(n)/factorial(n-r);

#include <stdio.h>
long factorial(int);
long find_ncr(int, int);
long find_npr(int, int);
int main(){
   int n, r;
   long ncr, npr;
   printf("Enter the value of n and r</p><p>");
   scanf("%d%d",&n,&r);
   ncr = find_ncr(n, r);
   npr = find_npr(n, r);
   printf("%dC%d = %ld</p><p>", n, r, ncr);
   printf("%dP%d = %ld</p><p>", n, r, npr);
   return 0;
}
long find_ncr(int n, int r) {
   long result;
   result = factorial(n)/(factorial(r)*factorial(n-r));
   return result;
}
long find_npr(int n, int r) {
   long result;
   result = factorial(n)/factorial(n-r);
   return result;
}
long factorial(int n) {
   int c;
   long result = 1;
   for (c = 1; c <= n; c++)
   result = result*c;
   return result;
}

Enter the value of n and r
5 2
5C2 = 10
5P2 = 20