Added a function to get the factorial of a number

mattrixwv/Algorithms.java

@@ -625,6 +625,38 @@ public class Algorithms{
 		fibNums.remove(fibNums.size() - 1);
 		return fibNums;
 	}
+	//This function returns the factorial of the number passed to it
+	public static Integer factorial(Integer num){
+		Integer fact = 1;	//The value of the factorial
+
+		//TODO: Throw an exception for values < 0
+		//Loop through every number up to and including num and add the product to the factorial
+		for(Integer cnt = 2;cnt.compareTo(num) <= 0;++cnt){
+			fact *= cnt;
+		}
+
+		return fact;
+	}
+	public static Long factorial(Long num){
+		Long fact = 1L;	//The value of the factorial
+
+		//Loop through every number up to and including num and add the product to the factorial
+		for(Long cnt = 2L;cnt.compareTo(num) <= 0;++cnt){
+			fact *= cnt;
+		}
+
+		return fact;
+	}
+	public static BigInteger factorial(BigInteger num){
+		BigInteger fact = BigInteger.valueOf(1L);
+
+		//Loop through every number up to and including num and add the product to the factorial
+		for(BigInteger cnt = BigInteger.TWO;cnt.compareTo(num) <= 0;cnt = cnt.add(BigInteger.ONE)){
+			fact = fact.multiply(cnt);
+		}
+
+		return fact;
+	}
 	//This function returns the sum of all elements in the list
 	public static Integer getSum(ArrayList<Integer> nums){
 		//If a blank list was passed to the function return 0 as the sum