File name as a variable

[Firepony]

I was wondering if anyone could tell me how i can use a vairable as a file name such as.

#include<iostream>
#include<fstream>
 
ifstream file;
string file = "test.dat";
 
file.open(file.c_str())
 
 

when i do it wont open the file.

[Ganon11]

You shouldn't name the string variable and the ifstream variable the same thing. Try

ifstream file;
string filename = "test.dat";
file.open(filename.c_str());

Also, make sure test.dat is an existing file.

[Firepony]

i have.

ifstream input;
string file = "test.txt";
input.open(file.c_str());
 

and the file exists. i put it in there myself.