Java program to find factorial of a number|in 6 ways

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

1. Integer variable num,fact are declared and initialized
2. the program finds the factorial of a number using for loop
3. 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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