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c++ setting string attribute value in class is throwing "Access violation reading location"

开发者 https://www.devze.com 2022-12-31 19:22 出处:网络
I am having some trouble getting this simple code to work: #pragma once #include <iostream> #include <string>

I am having some trouble getting this simple code to work:

#pragma once
#include <iostream>
#include <string>
using std::string;

class UserController;
#include "UserController.h"
class CreateUserView
{
public:
 CreateUserView(void);
 ~CreateUserView(void);
 UserController* controller;
 void showView();

 string name;
 string lastname;
 string address;
 string email;
 string dateOfBirth;
};

All i need is to set these attributes in the implementation with getline().

CreateUserView::CreateUserView(void)
{

}
void CreateUserView::showView()
{

 cout << endl << "  New User" << endl;
 cout << "--------------------------" << endl;
 cout << "  Name\t\t: ";
 getli开发者_StackOverflow社区ne(cin, name);

 cout <<  "  Lastname\t: ";
 getline(cin, lastname);

 cout << "  Email\t\t: ";
 getline(cin, email);


 cout << "  ===============================" << endl;
 cout << "   1. SAVE   2.CHANGE   3.CANCEL" << endl;
 cout << "  ===============================" << endl;
 cout << "  choice: ";
 int choice;
 cin >> choice;
 cin.ignore();

 controller->createUser_choice(choice);
}

I keep getting this "Access violation reading location" error at this line:

getline(cin, name);

what's the best way of assigning a value to an std::string attribute of a class? even name = "whatever" is throwing that error!!

thanks

EDIT: a UserController is instantiating the CreateUserView:

CreateUserView *_createUserView;

This how the CreateUserView is being instantiated:

void UserController::createUser()
{
    //Init the Create User View
    if(_createUserView == NULL)
    {
        _createUserView = new CreateUserView();
        _createUserView->controller = this;
    }
    _createUserView->showView();
}


You don't seem the initialize your variable properly:

CreateUserView *_createUserView;

Therefore it is a dangling pointer, not NULL (in C++, with a few exceptions, variables are not initialized automatically to 0). So here

if(_createUserView == NULL)
{
    _createUserView = new CreateUserView();
    _createUserView->controller = this;
}

the if block is not executed, and here

_createUserView->showView();

you get access violation. Initialize your pointer properly to NULL:

CreateUserView *_createUserView = NULL;


Try changing your declaration of the global:

CreateUserView *_createUserView = NULL;
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