检查密码 [英] Checking Password Code

问题描述

问题描述：

某些网站对密码规定了某些规则。编写一个检查字符串是否为有效密码的方法。假设密码规则如下：

Some Websites impose certain rules for passwords. Write a method that checks whether a string is a valid password. Suppose the password rule is as follows:

• 密码必须至少包含8个字符。


• 密码只包含字母和数字。


• 密码必须至少包含两位数。

编写一个程序，提示用户输入密码，如果遵循规则则显示有效密码，否则显示无效密码。

Write a program that prompts the user to enter a password and displays "valid password" if the rule is followed or "invalid password" otherwise.

这就是我到目前为止：

import java.util.*;  
import java.lang.String;  
import java.lang.Character;  

/**
 * @author CD
 * 12/2/2012
 * This class will check your password to make sure it fits the minimum set     requirements.
 */
public class CheckingPassword {  

    public static void main(String[] args) {  
        Scanner input = new Scanner(System.in);  
        System.out.print("Please enter a Password: ");  
        String password = input.next();  
        if (isValid(password)) {  
            System.out.println("Valid Password");  
        } else {  
            System.out.println("Invalid Password");  
        }  
    }  

    public static boolean isValid(String password) {  
        //return true if and only if password:
        //1. have at least eight characters.
        //2. consists of only letters and digits.
        //3. must contain at least two digits.
        if (password.length() < 8) {   
            return false;  
        } else {      
            char c;  
            int count = 1;   
            for (int i = 0; i < password.length() - 1; i++) {  
                c = password.charAt(i);  
                if (!Character.isLetterOrDigit(c)) {          
                    return false;  
                } else if (Character.isDigit(c)) {  
                    count++;  
                    if (count < 2)   {     
                        return false;  
                    }     
                }  
            }  
        }  
        return true;  
    }  
}

当我运行程序时，它只检查长度密码，我无法弄清楚如何确保它检查字母和数字，并在密码中至少有两位数。

When I run the program it only checks for the length of the password, I cannot figure out how to make sure it is checking for both letters and digits, and to have at least two digits in the password.

推荐答案

你几乎得到了它。但是有一些错误：

You almost got it. There are some errors though:

• 你没有迭代密码的所有字符（ i< password.length（） - 1 错误）


• 你的数字计数为1而不是0


• 一旦你遇到第一个数字就检查数字位数是否至少为2，而不是在你扫描完所有字符后检查它数

• you're not iterating over all the chars of the password (i < password.length() - 1 is wrong)
• you start with a digit count of 1 instead of 0
• you make the check that the count of digits is at least 2 as soon as you meet the first digit, instead of checking it after you have scanned all the characters

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