File handling String related question

[SUNIL TYATA]

I've declared the string realPath as
string realPath;
realPath = "c:/tc/matrix.txt";

when i use realPath for the path of file to open like

fstream infile;
infile.open(realPath, ios::in); //This line generate error like
///////////////////////////////////////
error msg:
1>.\read_matrix_table.cpp(31) : error C2664: 'void std::basic_fstream<_Elem,_Traits>::open(const wchar_t *,std::ios_base::openmode,int)' : cannot convert parameter 1 from 'std::string' to 'const wchar_t *'
1> with
1> [
1> _Elem=char,
1> _Traits=std::char_traits<char>
1> ]
1> No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called

//////////////////////////////////

[YarrOfDoom]

The problem is you're using a C++ string, but you actually need a C null-terminated string (don't worry, they're included in C++, C null-terminated string is just a fancy way of saying array of chars containing the characters of your string and with a null-value after those to mark the end of that string).

It's a bit stupid that fstream, as part of the standard library, doesn't support string, but luckily there's an easy workaround: you can use the c_str()-function to get the C-style string from your C++-style string.