binomic coefficient calculator

KombinacniCislo.java

import java.math.BigInteger;

/**
 * KombinacniCislo
 */
public class KombinacniCislo
{
    public static void main(String[] args)
    {
        int n = 0;
        int k = 0;
        try
        {
            n = Integer.parseInt(args[0]);
            k = Integer.parseInt(args[1]);
        }
        catch (Exception e)
        {
            System.out.println("expected two int arguments");
            System.exit(1);
        }

        int spaces = Math.abs(n) > Math.abs(k) ? Integer.toString(n).length() : Integer.toString(k).length();
        BigInteger out = binomialCoeff(n, k);

        System.out.printf("/ %s \\\n", indentString(Integer.toString(n), spaces));
        System.out.printf("| %s | = %s\n", indentString( "", spaces), out.signum() != 1 || n < 0 || k < 0 ? "Math error" : out);
        System.out.printf("\\ %s /\n", indentString(Integer.toString(k), spaces));
    }

    static String indentString(String a, int lenght)
    {
        for (int i = a.length(); i <= lenght; i++)
        {
            a = " " + a;
        }
        return a;
    }

    static BigInteger binomialCoeff(int n, int k)//could take biginteger as input as well, not necesary tho as it should not overflow
    {
        if (k == 1)
        {
            return BigInteger.valueOf(n);
        }
        else if (k == 0)
        {
            return new BigInteger("1");
        }
        else if (n < k)
        {
            return new BigInteger("-1");//math error
        }
        else
        {
            int n_limit, k_limit;//slight simplification of the algebraic formula
            BigInteger n_out = new BigInteger("1");
            BigInteger k_out = new BigInteger("1");

            if (k > n - k)
            {
                n_limit = k;
                k_limit = n - k;
            }
            else
            {
                n_limit = n-k;
                k_limit = k;
            }
            
            for (int i = 0; n - i > n_limit; i++)
            {
                n_out = n_out.multiply(BigInteger.valueOf(n -i));
            }
            for (int i = 0; k_limit - i > 1; i++)
            {
                k_out = k_out.multiply(BigInteger.valueOf(k_limit - i));
            }

            return n_out.divide(k_out);
        }
    }
    
}