16.Programming Nested If-else construct in c++.

C++ is arguably the most versatile language in common use. C++ allows for both high-performance code as well as expressive abstractions and design constructs. The language is not perfect but it does represent an excellent compromise between these potentially conflicting language capabilities. C++ combines "low-level" programming tailored to specific machine architectures with "high-level" programming, which can allow code to be completely abstracted from any particulars of the machine executing the program.The C++ language originally derives from the imperative language C. The defining feature which distinguishes C++ from C is support for Object-Oriented Programming (OOP). This makes C++ a multi-paradigm programming language.

Bjarne Stroustrup, a Computer Scientist from Bell Labs, was the designer and original implementer of C++ (originally named "C with Classes") during the 1980s as an enhancement to the C programming language. Enhancements started with the addition object-oriented concepts like classes, followed by, among many features, virtual functions, operator overloading, multiple inheritance, templates, and exception handling. These and other features are covered in detail in this book.

The C++ programming language is a standard recognized by the ANSI (The American National Standards Institute), BSI (The British Standards Institute), DIN (The German national standards organization), and several other national standards bodies, and was ratified in 1998 by the ISO (The International Standards Organization) as ISO/IEC 14882:1998, consists of two parts: the Core Language and the Standard Library; the latter includes the Standard Template Library and the Standard C Library (ANSI C 89).

Before you begin your journey to understand how to write programs using C++, it is important to understand a few key concepts that you may encounter. These concepts are not unique to C++, but are helpful to understanding computer programming in general. Readers who have experience in another programming language may wish to skim through this section, or skip it entirely.
There are many different kinds of programs in use today. From the operating system you use that makes sure everything works as it should, to the video games and music applications you use for entertainment, programs can fulfill many different purposes. What all programs (also called software or applications) have in common is that they all are made up of a sequence of instructions written, in some form or another, in a programming language. These instructions tell a computer what to do, and generally how to do it. Programs can contain anything from instructions to solve math problems, to how to behave when a video game character is shot in a game. The computer will follow the instructions of a program one instruction at a time from start to finish.

Although learning C is not a requirement for understanding C++, you must know how to use an imperative language. C++ will not make it easy for you to understand some of these deeper concepts, since in it you, the programmer, are given the greater range of freedom. There are many ways of doing things in C++. Understanding which options to choose will become the cornerstone of mastering the language.You should not learn C++ if you are solely interested in learning Object-oriented Programming. C++ offers some support for objects, but is still not truly Object-oriented, and consequently the nomenclature used and the approaches taken to solve problems will make it more difficult to learn and master those concepts. If you are truly interested in Object-oriented programming, you should learn Smalltalk.

As with all languages, C++ has a specific scope of application where it can truly shine. C++ is harder to learn than C and Java but more powerful than both. C++ enables you to abstract from the little things you have to deal with in C or other lower level languages but will grant you more control and responsibility than Java. As it will not provide the default features you can obtain in similar higher level languages, you will have to search and examine several external implementations of those features and freely select those that best serve your purposes (or implement your own solution).C++ is not the ideal first language. However, if you are willing to dedicate a more than passing interest in C++, then you can even learn it as your first language. Make sure to dedicate some time understanding the different paradigms and why C++ is a multi-paradigm, or hybrid, language.If you are approaching the learning process only to add another notch under your belt, that is, willing only to dedicate enough effort to understand its major quirks and learn something about its dark corners, then you would be best served in learning two other languages first.