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passing a string as file name to a ifstream

77 New Member
I want to pass a string as file name to a ifstream object, but I can't.
Expand|Select|Wrap|Line Numbers
  1. char cnt_string [6] = "";
  2. string f = "ss_";
  3. int cnt = 1;
  4. string seq = itoa(cnt, cnt_string, 10);
  5. string file = f+seq+".txt";
  7. ifstream fin( file );
The error at last line is:
error C2664: 'std::basic_ifs tream<_Elem,_Tr aits>::basic_if stream(const char *,std::ios_base ::openmode,int) ' : cannot convert parameter 1 from 'std::string' to 'const char *'
Feb 10 '10 #1
2 3990
9,065 Recognized Expert Moderator Expert
Use the member function std::string::c_ str()
Feb 10 '10 #2
77 New Member
Yes along with sstream header file it is very interesting
Expand|Select|Wrap|Line Numbers
  1. #include <sstream>
  2. ....
  3. string w1 = "seq_";
  4. int fileno = 1;
  5. string filename;
  6. stringstream str;
  7. str << w1 << fileno++ << ".txt";
  8. filename = str.str();
  9. ofstream fout( filename.c_str() );
  10. ...
Feb 10 '10 #3

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