tYSR20

168Part III: Introduction to ClassesActivating Our ObjectsYou use classes to simulate real-world objects. The Savings class tries torepresent a savings account. This allows you to think in terms of objectsrather than simply lines of code. The closer C++ objects are to the real world,the easier it is to deal with them in programs. This sounds simple enough.However, the Savings class doesn’t do a very good job of simulating a savingsaccount.Simulating real-world objectsReal-world objects have data-type properties such as account numbers andbalances, the same as the Savings class. This makes Savings a good startingpoint for describing a real object. But real-world objects do things. Ovenscook. Savings accounts accumulate interest, CDs charge a substantial penaltyfor early withdrawal — stuff like that.Functional programs “do things” via functions. A C++ program might callstrcmp() to compare two strings or max() to return the maximum of twovalues. In fact, Chapter 24 explains that even stream I/O (cin >> and cout