주민번호 랜덤 생성기(테스트)

import java.util.Random;
import java.util.Scanner;

public class JavaStudy04 {
public static void main(String[] args) {
System.out.println("[주민등록번호 계산]");

Scanner sc = new Scanner(System.in);

System.out.print("출생년도를 입력해 주세요.(yyyy):");
int year = sc.nextInt();


System.out.print("출생월을 입력해 주세요(mm):");
int month = sc.nextInt();

System.out.print("출생일을 입력해 주세요(dd):");
int date = sc.nextInt();

System.out.print("성별을 입력해 주세요(m/f):");
char gender = sc.next().charAt(0);

sc.close();

String frontPart = String.format("%02d%02d%02d", year % 100, month, date);

String genderCode;
if (gender == 'f') {
if (year < 2000) {
genderCode = "2";
} else {
genderCode = "4";
}
} else if (gender == 'm'){
if (year < 2000) {
genderCode = "1";
} else {
genderCode = "3";
}
}else {
System.out.println("잘못된 성별 입력입니다.");
return;
}


Random random = new Random();

int backPart = random.nextInt(999999) + 000001;

String randomNum = frontPart +"-"+ genderCode + backPart;

System.out.println(randomNum);
}
}