passing a string as file name to a ifstream

[mahmoodn]

I want to pass a string as file name to a ifstream object, but I can't.

char cnt_string [6] = "";
string f = "ss_";
int cnt = 1;
string seq = itoa(cnt, cnt_string, 10);
string file = f+seq+".txt";
 
ifstream fin( file );

The error at last line is:
error C2664: 'std::basic_ifstream<_Elem,_Traits>::basic_ifstrea m(const char *,std::ios_base::openmode,int)' : cannot convert parameter 1 from 'std::string' to 'const char *'

[Banfa]

Use the member function std::string::c_str()

[mahmoodn]

Yes along with sstream header file it is very interesting

#include <sstream>
....
string w1 = "seq_";
int fileno = 1;
string filename;
stringstream str;
str << w1 << fileno++ << ".txt";
filename = str.str();
ofstream fout( filename.c_str() );
...