[JAVA #18] 소인수분해

자바 (java) 소인수분해 (Factorization)

 

import java.util.Scanner;
 
// Factorization
public class FactorizationTest {
 
    public static void main(String[] args) {
 
        Scanner input = new Scanner(System.in);
        int num = input.nextInt();
        input.close();
 
        int a[] = new int[num];
        int t = 0;
 
        while (num != 1) {
            if (num >= 2) {
                for (int i = 2; i <= num; i++) {
                    if (num % i == 0) {
                        a[t] = i;
                        t++;
                        num = num/i;
                        break;
                    }
                }
            }
        }
 
        if (t == 1) {
            System.out.println(num + " is prime number");
        } else {
            for (int i = 0; i < t-1; i++) {
                System.out.print(a[i] + " x ");
            }
            System.out.println(a[t-1]);
        }
 
    }
 
}

 

 

자바 (java) 소인수분해 (Factorization)

 

import java.util.InputMismatchException;
import java.util.Scanner;
 
// Factorization
public class FactorizationTest {
 
    public static void main(String[] args) {
        execute();
    }
 
    private static void execute() {
        System.out.println(printResult(getInputNumber()));
    }
 
    private static int getInputNumber() {
        try (Scanner input = new Scanner(System.in)) {
            try {
                System.out.print("Input a number: ");
                int num = input.nextInt();
                if (num <= 1) throw new Exception();
                return num;
            } catch (InputMismatchException ime) {
                System.out.println("Input type integer!!");
                return getInputNumber();
            } catch (Exception e) {
                e.printStackTrace();
                try {
                    Thread.sleep(100);    // throws InterruptedException
                } catch (InterruptedException ie) {
                    ie.printStackTrace();
                }
                System.out.println("Input integer bigger than 1!!");
                return getInputNumber();
            }
        }
    }
 
    private static String printResult(int num) {
        int a[] = new int[num];
        int orgNum = num;
        int count = 0;
        while (num != 1) {
            for (int i = 2; i <= num; i++) {
                if (num % i == 0) {
                    a[count] = i;
                    count++;
                    num = num/i;
                    break;
                }
            }
        }
 
        StringBuffer sb = new StringBuffer();
        if (count != 1) {
            sb.append(orgNum + " = ");
            for (int i = 0; i < count-1; i++) {
                sb.append(a[i] + " x ");
            }
            sb.append(a[count-1]);
        } else {
            sb.append(orgNum + " is prime number");
        }
 
        return sb.toString();
    }
 
}