This program calculates nPr. Here There are n! (n factorial) permutations of n symbols. A r-permutation of n symbols is a permutation of r of them. There are n!/(n – r)! different r-permutations of n symbols.
using System; namespace Program { class Program { static void Main(string[] args) { int n, r, per, fact, fact1; Console.WriteLine("Enter the Value of 'n' and 'r' to find the Permutation:"); n = Convert.ToInt32(Console.ReadLine()); r = Convert.ToInt32(Console.ReadLine()); fact = n; for (int i = n - 1; i >= 1; i--) { fact = fact * i; } int number; number = n - r; fact1 = number; for (int i = number - 1; i >= 1; i--) { fact1 = fact1 * i; } per = fact / fact1; Console.WriteLine("Permutation : {0}", per); Console.ReadLine(); } } }
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