RWCString::operator[] doesn't compile in MSVC

When I try to compile RWCString's operator[] in MSVC

RWCString str("Hello World."); cout<< str[3];

I get the error error C2666 : 2 overloads have similar conversions.

char operator[](RWCString, size_t)

A call to str[3] is processed as a call to

char operator[](RWCString, int)

Because there is not an exact match for this function call, the compiler attempts to find a match by using implicit typecasting. The match that we expect:

char operator[](RWCString, size_t)

requires a single typecast from an int to a size_t.

RWCStrings can be typecast into char* by the operator

RWCString::operator const char*() const

Using this typecast, the compiler can also interpret str[3] as

char operator[](char*, int)

through one implicit typecast from an RWCString to a char*. It isn't clear to the compiler which function is best, so it returns the error.

There are two recommended fixes to this problem.

1. Always call str[] with an explicit typecast.
   str[(size_t) 3]
2. Never require implicit typecasting
   size_t index;
   str[index];

These fixes should work in most situations. If the recommended fixes are unacceptable, insert this block of code into your RWCString class definition inside of rw/cstring.h.

inline char operator[](int i)
{
    return operator[]((size_t) I);
}