Question

我正在为密码验证器编写类的程序。我需要密码至少6个字符，但我也将其限制为最多10个（不是必需的但是想要）。

该程序运行良好，我的其他验证工作，直到我尝试添加超过10个字符的密码。我可以通过并重新输入一个新密码，我收到的消息是它现在是一个有效的密码。但后来我得到了以下错误：

运行时检查失败＃2 - 变量'password'周围的堆栈已损坏。

如果设置宽度，我可以解决错误，但我知道这不是处理它的正确方法。另外我认为通过设置宽度，用户将无法输入除该大小以外的任何内容。

这是我的代码：

#include <iostream>
#include <iomanip>
#include <cstring>
#include <cctype>

using namespace std;

//Function prototypes
bool validatePassword(char *);                      //function to test pw requirements
bool validateUppercase(char *);                 //function to test for upper case value
bool validateLowercase(char *);                 //function to test for lowercase value
bool validateNumber(char *);                    //function to test for a number value
bool validateLength(char *);                    //function to test for password length

int main()
{
    //Variabes
    char password[11];                              //set the maximum number of char for password include the end     delimiter
    int size;                                       //size of the array

    //Prompt user to enter a password based on criteria

    cout << "Please enter a password that meets the following criteria: \n";
    cout << "1. A minimum of 6 characters up to a max of 10. \n";
    cout << "2. Contains atleast one uppercase and one lowercase character. \n";
    cout << "3. Contains atleast one number. \n\n";
    //cout << "****Please note if you have more the 10 characters \n";
    //cout << " the program will only accept the first 10***\n";
    cout << "\nPlease enter your password: ";
    cin >> password;
    //cin  >> setw(10) >> password;             //set this so I would not get a runtime error

    size = strlen(password);                        //determines the length of the password

    do
    {
        while (!validatePassword(password))     //if the functions returns a false value
        {
            cout << "\nYour password does not meet the requirements. ";
            cout << "\nEnter a new password: ";
            cin >> password;
            size = strlen(password);
        }
    } while (size > 10);

    if (validatePassword(password))
    {
        cout << "\nYour password " << password << " meets the requirements. \n";    //if the function returns a true value

    }

    system ("pause");

    return 0;

}

//This function calls the other validation functions 
bool validatePassword(char *pass)
{
int size = strlen(pass);
return (validateLength(pass) && validateUppercase(pass) &&         validateLowercase(pass) && validateNumber(pass) == true);
}

//This function validates the length of the password
bool validateLength (char *pass)
{
    int size = strlen(pass);
    if (size >= 6 && size < 10)
        return true;
    else
    {
        cout << "\n\nThe password you entered either contained to little or to many characters.";
        cout << "\nA minimum of 6 characters to a maximum of 10 is required.";
        return false;
    }
}

//This function checks to see if the password contains an uppercase char
bool validateUppercase(char *pass)
{
    int size = strlen(pass);
    for (int count = 0; count < size; count++)
    {
        if (isupper(pass[count]))
            return true;
    }

    cout << "\n\nThe password must contain at least one uppercase  character. ";
    return false;
}

 //This function checks to see if the password contains an lowercase char
 bool validateLowercase(char *pass) 
 {
    int size = strlen(pass);
    for (int count = 0; count < size; count++)
    {
        if (islower(pass[count]))
            return true;
    }

    cout << "\n\nThe password must contain at least one lowercase character. ";
    return false;
 }

//This function checks to see if the password contains an number char
bool validateNumber(char *pass)
{
    int size = strlen(pass);
    for (int count = 0; count < size; count++)
    {
        if (isdigit(pass[count]))
            return true;
    }

    cout << "\n\nThe password must contain at least one number. " ;
    return false;
 }

Answer 1

使用cstrings，运算符<<将读取一个字符串，并在缓冲区的末尾自动附加空字节字符，如果有足够的空间。

你分配一个11的缓冲区，所以当输入的密码高于10时，终止字符串的空字节不会出现，导致strlen等问题。实际上，strlen所做的只是读取输入并递增计数器直到遇到\0。

您现在有两个选择：

继续使用cstring并增加缓冲区的大小（足够高以避免意外），
切换到c ++的string类，这是一个能够动态增加的char数组（强烈推荐，here is a link to get started）。

另外，关于代码：你有很多不必要的东西。例如：

do
{
    while (!validatePassword(password))     //if the functions returns a false value
    {
        cout << "\nYour password does not meet the requirements. ";
        cout << "\nEnter a new password: ";
        cin >> password;
        size = strlen(password);
    }
} while (size > 10);

if (validatePassword(password))
{
    cout << "\nYour password " << password << " meets the requirements. \n";    //if the function returns a true value

}

可以替换为：

while (!validatePassword(password))
{
   cout << "\nYour password does not meet the requirements. ";
   cout << "\nEnter a new password: ";
   cin >> password;
}
cout << "\nYour password " << password << " meets the requirements. \n";

validatePassword调用validateLength来检查strlen(pass) <= 10，只有在密码正确时才能退出第一个循环。

另一个改进是将密码的大小传递给您的函数，以避免在任何地方调用strlen（在C中通常使用char *参数传递大小）。

堆栈溢出运行时错误c ++

1 个答案: