? ???? ?? ??? ?? Java ????? ??? ??? ???? ??? ??? ?? ?????. ???? ?? ?? ?? ?? ? ??? Java? ??? ????? ??? ????? ?????. Java? ????? ?????? ??? ?? ???? ?? ???????. Java?? ??? ??????? ????.

?? ????? ?? ?? ??

? ??, ????? ??, ????? ??? ?

“!”?? ???? ???? (???)? ??? ?? ??? ?? ??? ??? ?????. ?? ?? ??? 5? ?? ??? ??? 5???! = 5*4*3*2*1 = 120.

Java ????? ??? ??????

1. ??? ???? (?? ??).java

2. ???? ?? ?? java ??? ?????.

• ?. javac(?? ??).java

3. ?? ??? ??? ??? ?????.

4. ?? ??? ??? ??? ???.

• ?. java(?? ??)

??? ??? ??? Factorial? ?

??? ??? ??? ??? ??? ????.

?? 1 – ?? ?? ??

??? ?? ?? ??? ?? ??? Java ????? ???????.

public class Factorial
{
public static void main(String args[])
{int i, fact=1;
int number=5;
for(i=1;i<=number;i++)
{
fact=fact*i;
}
System.out.println("Factorial of "+number+" is: "+fact);
}
}

? ??? ?? ??? .java ???? ?????.

?? ??:

? ?? ??? "i"? "fact"? ???? ?? 1??, "number"? ??? ???? ??? 5? ????. For ??? ???? ??(?: 5)? ??? ??? i ?? ?? ?????. ???? ?? ?? ?? ??? ??? ???? ??? ? ?? ?????.

??:

? 2 – ??? ?? ??

? ?? ????? ???? ??? ??? ?? ?? ??? ?? ?? ??? ?? ??? ???? ????.

??? ?? ?? ??? ?? ??? ?????.

import java.util.Scanner;
class Facto{
public static void main(String args[]) {
int q, a, fact = 1;
System.out.println("Please Enter a number:");
Scanner in = new Scanner(System.in);
q = in.nextInt();
if ( q < 0 )
System.out.println("Please enter a number greater than 0:");
else {
for ( a = 1 ; a <= q ; a++ )
fact = fact*a;
System.out.println("Factorial of "+q+" is = "+fact);
}
}
}

?? ??? ????? ?? ??? ?????.

?? ??:

?? ?? ? ?? ?? ???? ??? ?????. ??? ?????. ??? ??? ??? ??? ? ???? ??? ??? "-" ?? ?? ??? ?? "0?? ? ??? ??????:"?? ???? ?????. ?? ??? ?????? ?????. ??? ?????. ?? ??? ????? ?? ??? ??? ? ?? ???? ?? ??? ?????.

??:

? 3 – ?? ?? ??

??? ????? ???? ?? ??? ?? ? ?????. ??? ????? ??? ????? ?? ?????. ?, ???? ??? ?? ?? ??? ??? ????. ?, ??? 2? ??? ?? ???.

??? ???? ?? ??? ?? ??? ??? ????? ?? ???? ???? ??? ?????. ?? ??? ??? ??? ????? ? ??? ?? ? ?? ? ?? ??? ????.

??

??? ??:

• ????? ?? ??? ????? ??? ?? ?? ??? ???? ?? ??? ?????.
• ? ??? ??? ??? ???? ??? ???? ??? ?? ??? ??? ?? ????? ? ?? ???? ?????.
• ??? ???? ???? ??? ?? ??? ??? ? ????.
• StackOverflowException: ??? ??? ???? ?? ?? ????? ? ??? ???? ??? ????.

?? ??? ?????:

public class FactorialExample2 {
static int factorial(int n){
if (n == 1)
return 1;
else
return(n * factorial(n-1));
}
public static void main(String[] args) {
System.out.println("Factorial of 5 is: "+factorial(5));
}
}

?? ?? ??? ????? ???? ??????.

?? ??:

The above code starts with a single int variable and checks if it is equal to 1; if yes, it returns one, as factorial for 1 is 1. If not equal to 1, it proceeds with the recursion function. Our int value, for example, is 5, so it’ll be like “5 * factorial(5-1)”, factorial is called here for the second time, which is another call. Then it returns again with a newer int value, which is 4, “4 * factorial(4-1)”, now it’ll be the third call to the recursion method. Now, the newer int value is 3, which means “3 * factorial(3-1)”, now it’ll be the fourth call, and the value will be 2, which means “2 * factorial(2-1)”. The int value will be one in the next recursive call, which will terminate the function here. While every call was made, its value was saved in a Stack, which is a LIFO method. So, for the final Output, the result will be “5*4*3*2*1 = 120.”

Compared to other methods, Recursion is quite difficult to understand and to implement, but if understood well and implemented wisely, it is a good tool.

Output:

It is highly recommended to use Recursion only in the case where writing an iterative code can be quite complex.

Now that we have learned various methods for implementing Factorial Calculations in Java Let’s explore a Built-in function that does the same work in a single line.

Example 4 – Using built-in Function

*) IntMath

Understanding the need for arithmetic operations over a value, a few functions specific to certain value types were written, we will see the Integer type value in work.

IntMath is a class for arithmetic calculations on an int value. IntMath class comes with a range of arithmetic operations, including factorial.

Syntax:

factorial (int n)

Conclusion –?Factorial in Java

We started with an introduction to java and how to run a java program. Then we learned about Factorial Calculation and various methods, including Recursion, to accomplish it.

Towards the end, we learned about IntMath; a Java Function primarily focused on Arithmetic operations. Java is a widely-used programming language; it comes with many features; in this article, we learned about Factorial Calculations in Java, which is a tiny aspect.

? ??? ??? ????? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!