자바 4주차 과제

1. (구글링 했음)

import java.util.*;
public class palindrome {
	public static void main(String[] args) {
		System.out.println("Enter a number : ");
		Scanner input = new Scanner(System.in);
		int num=input.nextInt();
		int newnum=reverse(num);
		isPalindrome(newnum);
	}
	public static int reverse(int number) {
		int reverse=0;
		while(number!=0) {
			int digit=number%10;
			reverse=reverse*10+digit;
			number/=10;
		}
		return reverse;
	}
	public static boolean isPalindrome(int number) {
		boolean isPalindrome=true;
		if(number==reverse(number)) {
			System.out.println("It is a palindrome.");
			isPalindrome=true;
		}
		else {
			System.out.println("It is not a palindrome.");
			isPalindrome=false;
		}
		return isPalindrome;
	}
}

2. (구글링 했음)

import java.util.*;
public class emirp {
	public static void main(String[] args) {
		final int NUMBER_OF_EMIRPS=120;
		final int NUMBER_OF_PRIMES_PER_LINE=10;
		int count=0;
		int number=2;
		
		while(count<NUMBER_OF_EMIRPS) {
			if(isPrime(number)&&isPrime(palindrome.reverse(number))&&number!=palindrome.reverse(number)) {
				count++;
				System.out.print(number+" ");
				
				if(count%10==0) {
					System.out.println();
				}
			}
			number++;
			}
		}
	
	public static boolean isPrime(int number) {
		for(int divisor=2;divisor<=number/2;divisor++) {
			if(number%divisor==0) {
				return false;
			}
	}
		return true;
	}
}