Opening a File for reading

[mahone]

Is there any possible way to read the file name from a string variable? doing something like this:

#include<iostream>
#include<string>
#include<fstream>
using namespace std;

int main()
{
  string str= "C:\CPP\try";
 ifstream in(s);
 return 0;
}

or maybe taking the filename from user in a string and then open that file for reading.

Thank You for reading.
Regards.

[modoran]

Yes.

#include<iostream>
#include<string>
#include<fstream>
using namespace std;

int main()
{
  string str;
cout << "Enter file name to open: \n";
cin >> str;
 ifstream in(str.c_str());


// do something

 return 0;
}

[mahone]

str.c_str();

What is that?
Please tell me...

[Lowest0ne]

I thought strings worked as is, the important thing being "C:\CPP\try.cpp"

[mahone]

I was trying the following exercise:

Create a Text class that contains a string object to hold the text of a file. Give it two constructors: a default constructor that takes a string argument that is the name of the file to open. When the second constructor is used, open the file and read the contents into the string member object. Add a member function contents() to return the string so (for example) it can be printed. In main(), open a file using Text and print the contents.

Based on useful info provided by modoran i came up with this code:

#include<iostream>
#include<string>
#include<fstream>
using namespace std;

class Text{
      string str;
      public:
             Text();
             Text(string);
             string contents();
             };
             
Text::Text()
{}

Text::Text(string s)
{
  ifstream in(s.c_str()); 
  string temp;
  while(getline(in,temp))
   str += temp+"\n";
}

string Text::contents()
{return str;}

int main()
{
    string newstr;
    cin>>newstr;
    Text txt(newstr);
    newstr= txt.contents();
    cout<<newstr<<endl;
    return 0;
}

But this is not working. And as I dont know nothing about the function c_str().I dont know how to correct the code.

Any help is really appreciated.
Thank You for reading.
Regards.

[S G H]

Well "This is not working" is quite generic... What does it do?

[mahone]

Sorry.. I tried with input:

"E:\CPP\try"
and
E:\CPP\try

but the program does not gives any output. There are no compiler or linker errors.