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Java program to find factorial of a number
In this tutorial, we will discuss the Java program to find factorial of a number|in 6 ways
In this post, we are going to learn how to find the factorial of a number or the given number in Java language
What is the factorial of a number (n)?
The factorial of a number (n) is the product of all positive integers from 1 up to n (n is the given number).
It is simply denoted by n!.
Example
if you want to find the factorial for number 5, you can follow this method.
Factorial of 5 will be 5*4*3*2*1=120
So, 5!=120.
Java program to find factorial of a number
Code to find factorial – using the stranded method
Program 1
class Factorial_Calc1
{
public static void main(String args[]){
int num=5,fact=1;
for(int i=1; i<=num; i++){
fact=fact*i;
}
System.out.println("Factorial of "+num+" is: "+fact);
}
}
When the above code is executed it produces the following output
Factorial of 5 is: 120
In this program
- Integer variable num,fact are declared and initialized
- the program finds the factorial of a number using for loop
- Then, the program is displayed the factorial of a number using System.out.println()
Code to find factorial – using the for loop
Program 2
import java.util.Scanner;
class Factorial_Calc2
{
public static void main(String args[]){
int num,fact=1;
Scanner scan=new Scanner(System.in); //create a scanner object for input
System.out.print("Enter the number for find factorial: ");
num=scan.nextInt();//get input from the user for num1
for(int i=1; i<=num; i++){
fact=fact*i;
}
System.out.println("Factorial of "+num+" is: "+fact);
}
}
When the above code is executed it produces the following output
Enter the number for find factorial: 6 Factorial of 6 is: 720
The program allows the user to enter a value and it finds and displays factorial of the given number using the for loop in Java language
Code to find factorial – using the while loop
Program 3
import java.util.Scanner;
class Factorial_Calc3
{
public static void main(String args[]){
int num,fact=1;
Scanner scan=new Scanner(System.in); //create a scanner object for input
System.out.print("Enter the number for find factorial: ");
num=scan.nextInt();//get input from the user for num1
int i=1;
while( i<=num){
fact=fact*i;
i++;
}
System.out.println("Factorial of "+num+" is: "+fact);
}
}
When the above code is executed it produces the following output
Enter the number for find factorial:5 Factorial of m5 is:120
The program allows the user to enter a value and it finds and displays factorial of the given number using while loop in Java language
Code to find factorial – using the do-while loop
Program 4
import java.util.Scanner;
class Factorial_Calc4
{
public static void main(String args[]){
int num,fact=1;
Scanner scan=new Scanner(System.in); //create a scanner object for input
System.out.print("Enter the number for find factorial: ");
num=scan.nextInt();//get input from the user for num1
int i=1;
do{
fact=fact*i;
i++;
}while( i<=num);
System.out.println("Factorial of "+num+" is: "+fact);
}
}
When the above code is executed it produces the following output
Enter the number for find factorial: 7 Factorial of 7 is: 5040
The program allows the user to enter a value and it finds and displays factorial of the given number using do-while loop Java language
Code to find factorial – using the method
Program 5
import java.util.Scanner;
class Factorial_Calc5
{
public static void main(String args[]){
int num;
Scanner scan=new Scanner(System.in); //create a scanner object for input
System.out.print("Enter the number for find factorial: ");
num=scan.nextInt();//get input from the user for num1
int result=factorial(num); //
System.out.println("Factorial of "+num+" is: "+result);
}
static int factorial(int n){//user defined method
int i=1,fact=1;
for(i=1; i<=n; i++){
fact=fact*i;
}
return fact;
}
}
When the above code is executed it produces the following output
Enter the number to find factorial:6 Factorial of 6 is:720
The program allows the user to enter a value and it finds and displays factorial of the given number using the user-defined method in java language
Code to find factorial – using recursion
Program 6
import java.util.Scanner;
class Factorial_Calc6
{
public static void main(String args[]){
int num;
Scanner scan=new Scanner(System.in); //create a scanner object for input
System.out.print("Enter the number for find factorial: ");
num=scan.nextInt();//get input from the user for num1
long result=factorial(num); //
System.out.println("Factorial of "+num+" is: "+result);
}
public static long factorial(int num){//recursive method
if(num>=1)
return num * factorial(num-1);
else
return 1;
}
}
When the above code is executed it produces the following output
Enter the number for find factorial: 8 factorial of 8 is: 40320
The program allows the user to enter a value and it finds and displays factorial of the given number using the recursive method in Java language
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