Java / 랜덤 임시 비밀번호 만들기 quiz

Quiz >1

 

 

package quiz;

 

import java.util.Random;

 

public class B12_TempPassword {

 

        public static void main(String[] args) {

        /*

         알파벳 대문자로 구성된 4자리 랜덤 임시 비밀번호 만들어 출력하는 프로그램

        

        */

                

        Random ran = new Random();

        int password = ran.nextInt(26)+65;

        int password1 = ran.nextInt(26)+65;

        int password2 = ran.nextInt(26)+65;

        int password3 = ran.nextInt(26)+65;

 

        

        System.out.print((char)password) ;

        System.out.print((char)password1) ;

        System.out.print((char)password2) ;

        System.out.print((char)password3) ;

        

        

        

        System.out.println();

        

        for(int i = 0; i < 4; ++i) {

                // 65~90 , 차이 26

                // char ch = (char)(Math.random() * 26 +65);

                // System.err.print(ch);

                System.out.print((char)(Math.random() * 26 + 65));

        }

        System.out.println();

 

}

 

}

 

 

 

---

Quiz>2

 

※

final : final 을 붙이고 선언한 변수는 값을 변경할 수가 없다.

 

변경하려고 하면 에러 발생

 

 

final String myCharSet ="abcdefghijklmnopqrstuvwxyz+"

+ "ABCDEFGHIJKLMNOPQURTUVWXYZ+"

+ "0123456789+"

+ "!@$%^&*()=+-_[]";

 

 

 

 

 

 

package quiz;

 

public class B12_TempPassword2 {

        

        /*

         대문자, 소문자, 특수문자, 숫자로 구성된 6자리 랜덤임시 비밀번호 만들어 출력하는 프로그램

        

         ※ 사용가능한 특수문자 - !@$%^&*()=+-_[]

        

        */

        public static void main(String[] args) {

 

                /*

                33 ! 37% 38& 42* 43+ 45 - 48~57 0~9 61 =

                64 @ 65 ~90 A~Z 91 [ 93 ] 94 ^ 95 _ 97~122 a~z

                */

                for (int i = 0; i < 6; ++i) {

                        char ch = (char) ((Math.random() * 90) + 33);

                        if (i <= 34 && i >= 36) {

                                continue;

                        } else if (i <= 39 && i >= 40) {

                                continue;

                        } else if (i == 44) {

                                continue;

                        } else if (i <= 46 && i >= 47) {

                                continue;

                        } else if (i <= 58 && i >= 60) {

                                continue;

                        } else if (i <= 62 && i >= 63) {

                                continue;

                        } else if (i == 92 && i == 96) {

                                continue;

                        } else {

                                System.out.print(ch);

                        }

                }

                System.out.println();

                

                // final : final 을 붙이고 선언한 변수는 값을 변경할 수가 없다.

                final String myCharSet ="abcdefghijklmnopqrstuvwxyz+"

                                + "ABCDEFGHIJKLMNOPQURTUVWXYZ+"

                                + "0123456789+"

                                + "!@$%^&*()=+-_[]";

                

                System.out.println("내 문자셋의 길이 : " + myCharSet.length());

                

                int len = myCharSet.length();

                String tempPassword = " ";

                for(int i=0; i<6; ++i) {

                        tempPassword +=

                        myCharSet.charAt((int)(Math.random() *len));

                }

                System.out.println("생성된 임시비밀번호 : " + tempPassword);

        }

}