Program crashing when I use IO

Hey dudes and dudettes :)

I'm creating my first text RPG, and I'm having a little problem with File IO. I'm writing a register system using File IO, and it crashes when I write to the file. I don't want to go any further as my Login system will work on the same principles, and If they don't work, then my game doesn't work. Here are the files that I think that you will need to help me with my problem:

RegisterMgr.h

Code:

---

#include <iostream>
#include <fstream>

class RegisterMgr
{
    public:
    std::string sRegister(std::string sUsername, std::string sPassword);
   
    private:
    std::string m_sUsername;
    std::string m_sPassword;
   
};

---

RegisterMgr.cpp

Code:

---

#include "RegisterMgr.h"

std::string RegisterMgr::sRegister(std::string sUsername, std::string sPassword)
{
    std::ofstream oRegister("Register.txt", std::ios::app);
    sUsername = m_sUsername;
    sPassword = m_sPassword;
    oRegister << sUsername << std::endl;
    oRegister << sPassword << std::endl;
    oRegister.close();
}

---

When I get up to entering the desired username and password, the program crashes :(

Any help would be greatly appreciated.

Are you sure the file is opened successfully?

It's (almost) never a good idea to open a file and start using it without checking.

Code:

---

std::ofstream oRegister("Register.txt", std::ios::app);
if (!oRegister) {
  ... file was not opened successfully
}

---

Hmm..... I'm pretty sure that it's opening successfully, as when i open the file outside of the program, manually, there are blank lines that have been written where the password and username should've been. Although I took your advice, and checked if the file was opened successfully, and as I predicted, it did. The crash happens after I write to the file.

I'm not too sure about the logics of your program, but it seems like you are just printing m_sUsername and m_sPassword to the file everytime, not the parametres, which is probably not what you want, because otherwise you wouldn't need the parametres.

If m_sUsername and m_sPassword are blank, it's not surprising that 2 blank lines are written to the file. Meaning the crash actaully happened AFTER the write.

(Note that you have 2 independent bugs here)

Thanks cyberfish! I fixed the IO problem thanks to you. The file writing works, but now I have to deal with the crashing :(

Post the smallest and simplest compilable program that demonstrates the error.

By the way:

• You should be using header inclusion guards.
• You only need to #include <string> in RegisterMgr.h
• You should #include <fstream>, <ostream>, "RegisterMgr.h" and optionally <string> in RegisterMgr.cpp.
• You should pass std::string objects by (const) reference unless you really want to copy them.
• The sRegister member function is declared as returning a std::string but does not actually return anything.

Using a debugger is the quickest way to find a crash.

Hmmm.... I have did as you said Laserlight, and rewrote the function as a void instead of a std::string, and I have gotten past the crash... kindov :) it crashes when it ends the function, which i'm not sure how to stop. Here is the full function:

RegisterMgr.h

Code:

---

#include <string>

class RegisterMgr
{
    public:
    void vRegister(std::string, std::string);
   
    private:
   
};

---

RegisterMgr.cpp

Code:

---

#include "RegisterMgr.h"
#include <fstream>
#include <ostream>

void RegisterMgr::vRegister(std::string sUsername, std::string sPassword)
{
    std::ofstream oRegister("Register.txt", std::ios::app);
    oRegister << sUsername << std::endl;
    oRegister << sPassword << std::endl;
    oRegister.close();
}

---

ResourceMgr.cpp

Code:

---

#include "ResourceMgr.h"
#include <iostream>

...............................................

void ResourceMgr::vDisplayRegisterMenu()
{
    std::system("cls");
    std::cout << "Welcome, please fill out the required fields to Register:" << std::endl;
    std::cout << "\nDesired Username: ";
    std::cin >> srUsername;
    std::cout << "\nDesired Password: ";
    std::cin >> srPassword;
    vRegister(srUsername, srPassword);
    std::system("cls");
    std::cout << "Thank you for registering " << srUsername << std::endl;
}

---

It crashes at the end of vDisplayRegisterMenu(); :S

Quote:

---

Originally Posted by legit

it crashes when it ends the function, which i'm not sure how to stop.

---

cyberfish made a good suggestion: use your debugger, e.g., place break points and step through the code until you detect a crash.

Quote:

---

Originally Posted by legit

Here is the full function:

---

It would be even better if you can give us something that we can compile and run. However, avoid giving us the entire code: give us the smallest and simplest compilable program that demonstrates the crash.

AHA! Sorry bout this everyone, but i've found the problem! I had std::cin.get() in Main.cpp and in my exit function, so I switched the std::cin.get() in Main.cpp to std::cin.ignore() and it seems to work now :) Thanks everyone!