👩🏼‍💻 カテゴリ

👩🏼‍💻 Stringクラス

👩🏼‍💻 Dateクラス

package pack_Date;

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Date;

public class Main {

	public static void main(String[] args) {

		Date date = new Date();
		System.out.println(date);
		
		String txt = date.toLocaleString();
		
		System.out.println("txt => " + txt);
		
		System.out.println("\n날짜만 표기");
		System.out.println(txt.substring(0, 13));
		
		System.out.println("\n시간만 표기");
		System.out.println(txt.substring(13)); //13부터 마지막까지~
		
		
		LocalDate localDate = LocalDate.now();
		
		int year = localDate.getYear();
		int month = localDate.getMonthValue();
		int day = localDate.getDayOfMonth();
		
		System.out.println();
		String dateRes = year + "-" + month + "-" + day;
		System.out.println(dateRes);
		
		System.out.println("\n\n--------------------\n\n");
		
		
		LocalDateTime myDateObj = LocalDateTime.now();
		
		System.out.println("Before formatting : " + myDateObj); //format => 형식
		
		//형식 적용 시작
		DateTimeFormatter myFormatObj
			= DateTimeFormatter.ofPattern("dd-MM-yyyy HH:mm:ss   a");
						 //or "dd/MM/yyyy HH:mm:ss   a"
                         			 //a => 오전/오후	
		
		String formattedDate = myDateObj.format(myFormatObj);
		System.out.println("After formatting : " + formattedDate);
	}

}

👩🏼‍💻 Formatクラス

🔎 Quiz)給与単位の印刷

package pack_Form;

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		
		System.out.print("세전급여를 입력해 주세요(단위. 원) : ");
		int money = scanner.nextInt();
		
		scanner.close();
		
		Money obj = new Money(money);
		String salary = obj.getSalary();
		System.out.print("실지급액 : " + salary + "원");
	}

}

package pack_Form;

public class Money {

	private int money;

	public Money(int money) {
		this.money = money;
	}
	
	public String getSalary() {
		double moneyParam = money - (money * 0.033);
		Format objFormat = new Format(moneyParam);
		String salary = objFormat.mtd_setForm();
		
		return salary;
	}
}

package pack_Form;

import java.text.NumberFormat;

public class Format {

	private double money;

	public Format(double money) {
		this.money = money;
	}
	
	public String mtd_setForm() {
		NumberFormat nf = NumberFormat.getInstance();
		String salary = nf.format(this.money);
		
		return salary;
	}
	
}

👩🏼‍💻 Mathクラス

特定の整数:Mathを生成します.floor(最低価格-最高価格+1)*Math.ランダム()+最大値;
ex)

🔎🤯 Quiz)身分証明書番号で出力

package pack_String;

import java.util.Scanner;

public class StringBuiltIn {

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		
		System.out.print("주민등록번호 입력 : ");
		String num = scanner.next();
		num = num.trim(); //입력값 앞뒤 공백 제거
		
		////////// 성별 구분 코드 //////////
		String genderCode = num.substring(7, 8);
		String gender = "";
		
		if (Integer.parseInt(genderCode) % 2 == 0) {
		//Integer.parseInt => String 타입의 숫자를 int 타입으로 변환!!
			gender = "Female";
		} else {
			gender = "Male";
		}
		
		////////// 나이 산출 코드 //////////
		String yearPrefix = "";
		
		switch (genderCode) {
		case "1", "2":
			yearPrefix = "19";
			break;

		case "3", "4":
			yearPrefix = "20";
			break;
		}
		
		String birthYear = yearPrefix + num.substring(0, 2);
		
//		LocalDate obj = LocalDate.now(); //많이 씀!
				
		int age = 2021 - Integer.parseInt(birthYear) + 1;
		
		System.out.println("나이 : " + age);
		System.out.println("성별 : " + gender);
		scanner.close();
		
	
	}

}

🔎🤯 Quiz)同じ値を持たない数字を出力する

package pack_RandomQuiz;

public class Main {

	public static void main(String[] args) {

		System.out.println("1부터 10사이의 난수 3개 출력");
		
		double[] rndNum = new double[3];
		int i = 0;
			
			while (true) { //무한 순환
				rndNum[i] = Math.floor(10*Math.random()+1);
				i++;
				
				if(i == 3) { //i가 3일 때 아래 내용 진행!
					
				if(! (rndNum[0] == rndNum[1] 
					|| rndNum[1] == rndNum[2]
					|| rndNum[2] == rndNum[0]) ){
					
					System.out.print((int)rndNum[0] + " ");
					System.out.print((int)rndNum[1] + " ");
					System.out.println((int)rndNum[2]);
					
					break;
					
				} else {
					i = 0;
				}
				}
		}
			
	}

}