Prior to C++11, there is no built-in function in C++ standard library which can be used to convert numbers such as interger and double number to string.  There are many ways which can convert number to string. Since C++ is C compatible, we can use itoa() function to convert an integer to C style string. But this one can only convert integer to string, not double. For different types of numbers, we need to use different functions.string s = string(itoa(a));Actually, we can also use stringstream in C++ to convert number to string.  Also, here since we want to convert different types of...