C++ 二进制输入/输出文件读/写访问破坏

Question

i trying to read pass string from a file and then comparing it if the pass is correct but read/write access voilation occurs. if i compare it with account number int then works fine but hwen compare with strig then this voilation error comes and the other thing is that afer that i cannot use that account instantiate stored in binary file even if i try to read that istantiate with int acoount number. But when i create new instatiate and store it in file then the new insatitae is available to comapre with int until it is not compared with string

here is my class**
    
class account {
    std::string name , pass;
    int acno , balance;
    public:
        int getAcno()
        {
            return acno;
        }
        std::string getPass()
        {
            return pass;
        }
            std::string getName()
            {
                return name;
            }
            int getBalance()
            {
                return balance;
            }
            void createAccount()
            {
                std::cout << "\n\tEnter the account number : ";
                std::cin >> acno;
                std::cin.ignore(32767, '\n');
                std::cout << "\n\tEnter the account pass : ";
                std::cin >> pass;
                std::cin.ignore(32767, '\n');
                std::cout << "\n\tEnter the name of account holder : ";
                std::getline(std::cin , name);
                std::cin.ignore(32767, '\n');
                std::cout << "\n\tEnter the current balance : ";
                std::cin >> balance;
                std::cin.ignore(32767, '\n');
                
            }
            void showAccount()
            {
                std::cout << "\n\n\tAccount number : " << acno;
                std::cout << "\n\tAccount holder name : " << name;
                std::cout << "\n\tBalance : " << balance;
            }
    
    };
    '''
        here is my access function 
        void login()
        {
            std::ifstream infile{ "user.dat" , std::ios::binary | std::ios::in};
            if (!infile)
            {
                std::cout << "\n\tError! cannot open the file";
                return;
            }
        
            int acno;
            std::string pass = "jam";
            std::cout << "\n\n\tEnter the account number: ";
            std::cin >> acno;
            std::cout << "pass";
            std::cin >> pass;
            account new_account;
            bool flag = false;
            while (infile.read((char*)&new_account, sizeof(new_account)))
            {
                if (new_account.getPass() == pass)
                {
                    new_account.showAccount();
                    flag = true;
                    break;
                }
            }
            if (flag == false)
            {
                std::cout << "\n\tSorry! Account number not found!";
                    }
                }

Answer 1

As in the comments mentioned you should not write your objects like they are stored in RAM especially if they have some "reference-like" semantics like the subobject of your account std::string.

What you write in this case is typically a pointer and a length. The problem is, when you read the data again, the loaded pointer points to "garbage".