錯誤3錯誤LNK2019：無法解析的外部符號「市民：無效__thiscall

Question

我不斷收到這個錯誤，它不會讓我編譯誰能幫我

這是UsernamePasswordValidator.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; 
} 

這是我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; 
}; 

最後，這是我此代碼驅動程序。

#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

你有上面的方法聲明，但沒有定義。 鏈接期間鏈接器無法找到把定義爲setPassword

在UsernamePasswordValidator.cpp添加以下內容：

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