The factorial(int n) method of Guava’s LongMath Class returns the product of the first n positive integers, which is n!.
public static long factorial(int n)
Parameter: The method accepts only one parameter n which is of integer type and is to be used to find the factorial.
Return Value: This method return following values:
- This method returns 1 if n is 0.
- This method returns product of the first n positive integers if the result fits in a long.
- This method returns Long.MAX_VALUE if the result does not fit in a long.
Exceptions: The method factorial(int n) throws IllegalArgumentException if n is negative.
Below programs illustrate the use of LongMath.factorial() method:
factorial of 10 is : 3628800 factorial of 12 is : 479001600
Example 2 :
java.lang.IllegalArgumentException: n (-5) must be >= 0
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