[JAVA #10] 자바 팩토리얼

# 자바 (java) 팩토리얼

 

1. 팩토리얼

 

import java.util.Scanner;
 
// factorial of input integer
public class FactorialTest {
    public static void main(String[] args) {
        
        int n, fact = 1;
        int first = 0;
        Scanner input = new Scanner(System.in);
        System.out.print("Input an integer: ");
        n = input.nextInt();
        first = n;
        
        while (n > 0) {
            fact = fact * n;
            n = n - 1;
        }
        System.out.println("factorial of input number " + first + " is " + fact);
        
        input.close();
        
    }
}

 

 

 

2. 자바 팩토리얼 클래스

 

import java.util.Scanner;
 
// factorial of input integer using class
class Factorial {
    
    int fact = 1;
    public int factorialTest(int num) {
        while (num > 0) {
            fact = fact * num;
            num = num - 1;
        }
        return fact;
    }
}
 
public class FactorialTest {
 
    public static void main(String[] args) {
        
        int num;
        Scanner input = new Scanner(System.in);
        System.out.print("Input an integer: ");
        num = input.nextInt();
        input.close();
        Factorial fact = new Factorial();
        int result = fact.factorialTest(num);
        System.out.println("factorial of input number " + num + " is " + result);
        
    }
 
}
 

 

 

3. 자바 팩토리얼 재귀호출

 

import java.util.Scanner;
 
// factorial (recursive)
class FactorialRecursive {
    int fact = 1;
    public int factorial(int num) {
        return (num > 0) ? num * factorial(num - 1) : 1;
    }
}
 
public class FactorialTest {
 
    public static void main(String[] args) {
        int num;
        Scanner input = new Scanner(System.in);
        input.close();
        num = input.nextInt();
        FactorialRecursive factorialRecursive = new FactorialRecursive();
        int result = factorialRecursive.factorial(num);
        System.out.println("factorial of input number " + num + " is " + result);
    }
 
}