Preserve Code Safety with Conversion Operators

ertain objects must be converted to a low-level representation and vice versa. Programmers using std::string objects, for instance, have to convert them to bare char pointers, as in the following example:

string inf="mydata.txt";
ifstream infile(inf.c_str());//const char* required

Similarly, POSIX programmers need to convert <fstream> objects to file descriptors to use native system calls.

How to automate conversions of objects to their underlying types without compromising code safety?

Use conversion operators and explicit constructors to create objects with a dual-interface while avoiding ill-behaved conversions.