open file with different names

[siato]

I want to open a file in my code ( Visual C++ 2005) in the way that the file name contains some variables.
while i using f.open("file_name.ext") ; i prefer to put a string instead of fix name

string s;
s="name1.ext";
ofstream f;
f.open(s);
 

i receive an error
error C2664: 'void std::basic_ofstream<_Elem,_Traits>::open(const wchar_t *,std::ios_base::openmode,int)' : cannot convert parameter 1 from 'std::string' to 'const wchar_t *'
with
[
_Elem=char,
_Traits=std::char_traits<char>
]
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called



help me out plz

[oler1s]

It’s because, rather surprisingly, the fstream open member function requires a char* string (i.e. C string), and is not designed to handle C++ strings as well. But it’s no problem if you use a C++ string. Fortunately, the C++ string class has a member function called c_str() that returns a temporary C string. So instead of

f.open(s)

you want

f.open(s.c_str())

.