user defined file I/O

[montablac]

ok in my code it has at a point where the user enter there name,the code then adds ".txt" to the end of it and 'trys' to open the file

now before anyone sais anything,i am a complete and utter newb

ill give you a snipit of the code

cout<<"\nusername:";
    getline(cin,user,'\n');
    cin.ignore();
    user = user + txt;
    ifstream userfile ( user );
    if ( !userfile.is_open() ){
         cout<<"user dosent exist";
         cin.get();
         cin.ignore();
         }

i HAVE declared the two strings,one has as its starting operator ".txt",im also using fstream and iostream and am using namespace std

any help for a new guy?

[hk_mp5kpdw]

ifstream userfile ( user.c_str() );

The constructor for file streams that automatically opens a file given as the constructor's argument expects a C-style NULL terminated character string as an argument and not a C++ string container object. Thankfully, C++ strings have the handy c_str() member function which returns a C-style NULL terminated character string for you to use as I have above.

[7stud]

any help for a new guy?

1) You should always post code that shows where and how the variables are declared. It isn't productive to speculate what you might actually have for code.

2) You don't need to declare a string variable named txt and assign it ".txt", e.g.

string txt = ".txt";

All you need to do is this:

user = user + ".txt";

3)

i HAVE declared the two strings,one has as its starting operator ".txt"

The terminology goes like this: "I have declared two strings and one has a starting value of ".txt".

4)Your problem is this line:

ifstream userfile ( user );

You have a string type in between the parentheses: the variable user is a string type. You have to use a different type between the parentheses for your program to work. To get the needed type from a string type, you have to use the string function c_str(). hk_mp5kpdw posted how to do that.

Basically, in C++ whenever you put a variable between the parentheses of a function, it has to be the correct type. The function is expecting a specific type, and if you don't feed it the exact type it is expecting, you will get an error.

[montablac]

thank you for that

and im sory i got a few things wrong with posting my code and terminology

i hope that things can get a bit better from now on