newbie question about file streaming with variable filename.

[Saad85]

okay, so to write something to a file is simple enough, but now i need to write many things to many files. the actual writing part i can deal with, but c++ gives me a compiler error when i try to open a file-out stream using a variable to hold the file name.

my code is this:

code:

#include<iostream> #include<fstream> #include<string> #include<sstream> #include<stdlib.h> using namespace std; string to_string( int val ) { stringstream stream; stream << val; return stream.str(); } int main(){         string x;         int i=1;         //for (i=1;i<=5;i++){                 x=to_string(i)+".txt";                 cout<<x<<endl;                                 ofstream fout(x);                 if (fout) fout << "this writes to file";                 fout.close();         //}                 }

the problematic line is "ofstream fout(x);"
it works fine if i put "ofstream fout("1.txt");" but it won't let me use the variable in there. is there any way i can do this?

(as you can see, i plan to later use a for loop to do this for five seperate files)

[Saad]

The ofstream constructor uses a C-Style string to pass the file name. Luckily the std::string class has a method to convert an std::string to a C-Style string.

You should replace

c++:

ofstream fout (x);

With

c++:

ofstream fout (x.c_str());

Some more information on c_str() method
Information on the ofstream constructor

[michaelp]

Also, you should change <stdlib.h> to <cstdlib>

[Saad85]

ah, thanks guys