Factorial program in java

Hey guys!! In this post we are going to learn factorial program in java. Factorial java is the common java program. Factorial is nothing but the product of all numbers less than or equal to given number. Denoted as n! For example,

6! = 6 * 5 * 4 * 3 * 2 * 1 = 720 (6! means 6 factorial)

4! = 4 * 3 * 2 * 1 = 24 (4! means 4 factorial)

Let’s see java program to find factorial using for loop,

```public class FactorialDemo
{
public static void main(String[] args)
{
int number = 6, factorial = 1;
for(int a = 1; a <= number; a++)
{
factorial = factorial * a;
}
System.out.println("Factorial of " + number + " is : " + factorial);
}
}

```

Output:

Factorial of 6 is : 720

Using recursion

```public class FactorialRecursion
{
public static void main(String[] args)
{
int factorial = 1;
int number = 6;
factorial = factorialFunction(number);
System.out.println("Factorial of " + number + " is : " + factorial);
}

static int factorialFunction(int num)
{
if(num == 0)
{
return 1;
}
else
{
return(num * factorialFunction(num - 1));
}
}
}

```

Output:

Factorial of 6 is : 720

Using while loop

```import java.util.Scanner;

public class FactorialWhile
{
public static void main(String[] args)
{
int number, factorial = 1;
Scanner sc = new Scanner(System.in);
System.out.println("Please enter a number to find its factorial : ");
number = sc.nextInt();

int a = 1;
while(a <= number)
{
factorial = factorial * a;
a++;
}
System.out.println("Factorial of " + number + " is : " + factorial);
sc.close();
}
}

```

Output:

Please enter a number to find its factorial : 5
Factorial of 6 is : 120

Using do while loop

```import java.util.Scanner;

public class FactorialDoWhile
{
public static void main(String[] args)
{
int number, factorial = 1;
Scanner sc = new Scanner(System.in);
System.out.println("Please enter a number to find its factorial : ");
number = sc.nextInt();

int a = 1;
do
{
factorial = factorial * a;
a++;
}
while(a <= number);
System.out.println("Factorial of " + number + " is : " + factorial);
sc.close();
}
}

```

Output:

Please enter a number to find its factorial : 7
Factorial of 7 is : 5040