11.15. Wrap-Up

In this chapter, you learned how to build more robust classes by defining overloaded operators that enable programmers to treat objects of your classes as if they were fundamental C++ data types. We presented basic operator overloading concepts, as well as several restrictions that the C++ standard places on overloaded operators. You learned reasons for implementing overloaded operators as member functions or as global functions. We discussed the differences between overloading unary and binary operators as member functions and global functions. With global functions, we showed how to input and output objects of our classes using the overloaded stream extraction and stream insertion operators, respectively. We showed a special syntax that is required to differentiate between the prefix and postfix versions of the increment (++) operator. We also demonstrated standard C++ class string, which makes extensive use of overloaded operators to create a robust, reusable class that can replace C-style, pointer-based strings. Finally, you learned how to use keyword explicit to prevent the compiler from using a single-argument constructor to perform implicit conversions. In the next chapter, we continue our discussion of classes by introducing a form of software reuse called inheritance. We'll see that when classes share common attributes and behaviors, it is possible to define those attributes and behaviors in a common "base" class and "inherit" those capabilities into new class definitions.