Java Guava | Longs.factorial(int n) method with Examples
The factorial(int n) method of Guava’s LongMath Class returns the product of the first n positive integers, which is n!.
Syntax :
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:
Example 1:
import java.math.RoundingMode;
import com.google.common.math.LongMath;
class GFG {
public static void main(String args[])
{
int n1 = 10 ;
long ans1 = LongMath.factorial(n1);
System.out.println( "factorial of "
+ n1 + " is : "
+ ans1);
int n2 = 12 ;
long ans2 = LongMath.factorial(n2);
System.out.println( "factorial of "
+ n2 + " is : "
+ ans2);
}
}
|
Output:
factorial of 10 is : 3628800
factorial of 12 is : 479001600
Example 2 :
import java.math.RoundingMode;
import com.google.common.math.LongMath;
class GFG {
static long findFact( int n)
{
try {
long ans = LongMath.factorial(n);
return ans;
}
catch (Exception e) {
System.out.println(e);
return - 1 ;
}
}
public static void main(String args[])
{
int n = - 5 ;
try {
findFact(n);
}
catch (Exception e) {
System.out.println(e);
}
}
}
|
Output:
java.lang.IllegalArgumentException: n (-5) must be >= 0
Reference: https://google.github.io/guava/releases/20.0/api/docs/com/google/common/math/LongMath.html#factorial-int-
Last Updated :
29 Jan, 2019
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