The function BinomCoeff calculates the binomial coefficient (n,k), which is the number of possible combinations when drawing k items out of a total set of n. The binomial coefficient is defined by the following formula:
The parameters n, and k have to be positive, with n >= k. If this condition is not fulfilled, BinomCoeff returns a zero value.
Please note that the binomial coefficient may become too large to be returned as longint value. In this case the function returns a value of -1. If you expect large binomial coefficients you maybe want to use the function LnBinomCoeff, which calculates the natural logarithm of it.