calculate static method

BigInt calculate(int n)

Calculates the factorial of a non-negative integer n using an iterative approach.

The factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n.

Definition:

• 0! = 1
• n! = n * (n-1) * (n-2) * ... * 1 for n > 0

Parameters:

• n: The non-negative integer for which to calculate the factorial.

Returns: A BigInt representing the factorial of n.

Throws:

• ArgumentError: If n is a negative number.

Implementation

static BigInt calculate(int n) {
  if (n < 0) {
    throw ArgumentError('Factorial is not defined for negative numbers.');
  }

  if (n == 0) {
    return BigInt.one;
  }

  var result = BigInt.one;

  for (int i = 1; i <= n; i++) {
    result *= BigInt.from(i);
  }

  return result;
}