6.Class and Object in c++ defining get( ) and set( ) methods to initialize the private members
One of the main reason for preferring C++ over simpler, higher-level programming languages is that C++ allows the development of complex software in a way that makes more efficient use of hardware resources than when using these other languages. The language does not guarantee efficient code automatically, but provides a toolchest that aids programmers in the pursuit of efficiency. Sloppy C++ code may be no more efficient than higher-level implementations of the same algorithms, but a good C++ programmer with knowledge of the language can write software that is efficient from the first cut and then optimize the code further.
Often, there is no single solution to a programming problem that is optimal for all cases. Thus, optimization generally does not mean writing optimally performing software; rather, it means incrementally changing (refactoring) software to increase it's performance, bringing it closer to the optimum.Such optimization requires that the software source is written in a sufficiently modular way that performance critical parts can be isolated. With suitably written code, it then requires the use of tools, libraries, knowledge and time to change those parts in a way that increases the overall execution speed of the software.
Nowadays, many optimizations are already performed by compilers and are no longer the programmer's burden. This book discusses higher-level optimizations that present-day compilers are not (yet) able to perform.