c++ - 错误3错误LNK2019 : unresolved external symbol "public: void __thiscall

Question

我一直收到这个错误，它不允许我编译。谁能帮帮我？

这是用户名密码验证器.cpp

#include "UsernamePasswordValidator.h"
#include <cctype>
#include <iostream>
#include <string>

using namespace std;


UsernamePasswordValidator::UsernamePasswordValidator()
{
    myUsername = " ";
    myPassword = " ";
    my_ValidationFailed = true;
}


void UsernamePasswordValidator::setUsername(string username)
{
    myUsername = username;
}

void UsernamePasswordValidator::setUsernameViaCString(char *username)
{
    myUsername = username;
}

void UsernamePasswordValidator::setPasswordViaCString(char *password)
{
    myPassword = password;
}

bool UsernamePasswordValidator::isValid()
{
    int upperCase = 0, numCount = 0, lowerCase = 0;

    for (int u = 0; u < myUsername.length(); u++)
    {

        if ( !(isalnum(myUsername.at(u))) ) 
        {
            my_ReasonWhyItFailed = "Username must contain both letters and numbers!";
            return (my_ValidationFailed = false);
        }  

            if ( isupper(myUsername.at(u)) ) 
            {
                upperCase++;
             }

                if ( islower(myUsername.at(u)) )
                {
                    lowerCase++;
                }

                    if( isdigit(myUsername.at(u)) )
                    {
                        numCount++;
                    }

    }

if (myUsername.length() < 8)
{
    my_ReasonWhyItFailed = "The username is too short!\n";

    return (my_ValidationFailed = false);
}

    else if (upperCase == 0)
    {
        my_ReasonWhyItFailed = "You need at least one Upper case letter.\n";

        return (my_ValidationFailed = false);
    }

        else if (lowerCase == 0)
        {
            my_ReasonWhyItFailed = "You need at least one lowercase letter.\n";

            return (my_ValidationFailed = false);
        }

            else if (numCount == 0)
            {
                my_ReasonWhyItFailed = "The username needs a number.\n";

                return (my_ValidationFailed = false);
            }


upperCase = lowerCase = numCount = 0;


for (int p = 0; p < myPassword.length(); p++) 
{

    if ( !(isalnum(myPassword.at(p))) ) 
    {
        my_ReasonWhyItFailed = "The password needs letters and numbers.";

        return (my_ValidationFailed = false);
    }  

        if ( isupper(myPassword.at(p)) )
        {
            upperCase++;
        }

            if ( islower(myPassword.at(p)) )
            {
                lowerCase++;
            }

                if( isdigit(myPassword.at(p)) )
                {
                numCount++;
                }
} 

if (myPassword.length() < 8)
{
    my_ReasonWhyItFailed = "password does not contain enough characters.";

    my_ValidationFailed = false;
} 

    else if (upperCase == 0)
    {
        my_ReasonWhyItFailed = "password does not contain a uppercase value.";

        my_ValidationFailed = false;
    } 

        else if (lowerCase == 0)
        {
            my_ReasonWhyItFailed = "password does not contain a lowercase value.";

            my_ValidationFailed = false;
        }

        else if (numCount == 0)
        {
            my_ReasonWhyItFailed = "password does not contain a number.";

            my_ValidationFailed = false;
        }

            else if (myPassword.find(myUsername) != string::npos)
            {
                my_ReasonWhyItFailed = "password cannot contain username.";

                my_ValidationFailed = false;
            } 

return my_ValidationFailed;
}


string UsernamePasswordValidator::reasonForFailure()
{

    return my_ReasonWhyItFailed;

}


void UsernamePasswordValidator::reset()
{
    myPassword = "";
    myUsername = "";
    my_ValidationFailed = true;
}

这是我的 UsernamePasswordValidator.h 文件。

#include <iostream>
#include <cctype>
#include <string>

using namespace std;

class UsernamePasswordValidator
{

public:

    UsernamePasswordValidator();

    void setUsername(string username);
    void setPassword(string password);
    void reset();
    void setUsernameViaCString(char * username);
    void setPasswordViaCString(char * password);

    string reasonForFailure();

    bool isValid();

private:
    string myUsername, myPassword, my_ReasonWhyItFailed;
        bool my_ValidationFailed;
};

最后，这是我的代码驱动程序。

#include <iostream>
#include <cctype>
#include <string>
#include "UsernamePasswordValidator.h"

using namespace std;

int main()
{
    UsernamePasswordValidator upv;

    string user, pass;
    char * badpassword = "data      ";
    char * goodpassword = "goodPassword";

    cout << "CS52 Username/Password Validator \n";
    cout << "\n Username:\n";
    getline( cin, user );  // reads a whole line of input

    cout << "\n Password: \n";
    getline( cin, pass );  // reads a whole line of input

    upv.setUsername( user );
    upv.setPassword( pass );

    if (upv.isValid() )
    {
        cout << "The Username/Password combination is valid!" << endl;
    }
        else
        {
            cout << upv.reasonForFailure( ) << endl;
        }

    upv.reset( );

    upv.setUsername( user );
    upv.setPassword( badpassword );

    if (upv.isValid() )
    {
        cout << "The Username/Password combination is valid!" << endl;
    }
         else
        {
            cout << upv.reasonForFailure( ) << endl;
        }

    return 0;
}

Answer 1

您声明了上述方法但未定义。在链接期间，链接器找不到 setPassword 的定义

在 UsernamePasswordValidator.cpp 中添加以下内容:

void UsernamePasswordValidator::setPassword(string password)
{
    myPassword = password;
}