C# Code Snippets

C# Combination Function

Visual C# Kicks

Calculates the number of combinations from choosing r elements from a set of n total elements. The function takes advantage of the fact that the number of combinations is symmetric (based on r) to avoid calculating large numbers when possible.

Platform: .NET Framework 2.0

public long Factorial(long x, long lowerBound)
    long fact = 1;
    while (x >= 1 && x > lowerBound)
        fact *= x;
    return fact;

public long Choose(long n, long r)
    return (long)((double)Factorial(n, Math.Max(n - r, r)) / (Factorial(Math.Min(n - r, r))));

Back to C# Code Snippet List

Other C# Articles
Unable to connect to database! Please try again later.