Object oriented programming 7 first steps in oop using c++

Object oriented programming 7 first steps in oop using c++

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  Object Oriented Programming:7 First Steps in OOP using C++ Prof Neeraj Bhargava Vaibhav Khanna Department of Computer Science School of Engineering and Systems Sciences Maharshi Dayanand Saraswati University Ajmer
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  Benefits of OOP •Through inheritance, we can eliminate redundant code extend the use of existing • Classes. • We can build programs from the standard working modules that communicate with one another, rather than having to start writing the code from scratch. • This leads to saving of development time and higher productivity. • The principle of data hiding helps the programmer to build secure program that can not be invaded by code in other parts of a programs. • It is possible to have multiple instances of an object to co-exist without any interference.
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  Benefits of OOP •It is possible to map object in the problem domain to those in the program. • It is easy to partition the work in a project based on objects. • The data-centered design approach enables us to capture more detail of a model can implemental form. • Object-oriented system can be easily upgraded from small to large system. • Message passing techniques for communication between objects makes to interface descriptions with external systems much simpler. • Software complexity can be easily managed.
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  Application of OOP •Real-time system • Simulation and modeling • Object-oriented data bases • Hypertext, Hypermedia, and expert system • AI and expert systems • Neural networks and parallel programming • Decision support and office automation systems • CIM/CAM/CAD systems
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  Introduction of C++ •C++ is an object-oriented programming language. • It was developed by Bjarne Stroustrup at AT&T Bell Laboratories in Murray Hill, New Jersey, USA, in the early 1980’s. • Stroustrup, an admirer of Simula67 and a strong supporter of C, wanted to combine the best of both the languages and create a more powerful language that could support object-oriented programming features and still retain the power and elegance of C. • The result was C++. Therefore, C++ is an extension of C with a major addition of the class construct feature of Simula67. • Since the class was a major addition to the original C language, Stroustrup initially called the new language ‘C with classes’. • However, later in 1983, the name was changed to C++. The idea of C++ comes from the C increment operator ++, thereby suggesting that C++ is an augmented version of C.
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  Introduction of C++ •The most important facilities that C++ adds on to C are – classes, inheritance, – function overloading and – operator overloading. – These features enable creating of abstract data types, – inherit properties from existing data types and support polymorphism, thereby making C++ a truly object-oriented language.
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  Printing A Stringin C++ • #include<iostream> • Using namespace std; • int main() • { • cout<< “c++ is a very powerful Object Oriented Programming Language n” ; • return 0; • }
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  Program feature • LikeC, the C++ program is a collection of function. • The above example contain only one function main(). As usual execution begins at main(). • Every C++ program must have a main(). • C++ is a free form language. • With a few exception, the compiler ignore carriage return and white spaces. • Like C, the C++ statements terminate with semicolons.
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  Comments • C++ commentsymbol // (double slash) is used for single line comments • Comment start with a double slash symbol and terminate at the end of the line. • A comment may start anywhere in the line, and whatever follows till the end of the line is ignored. (Note that there is no closing symbol) • The C comment symbols /*, */ are still valid and are more suitable for multiline comments. The following comment is allowed: • /* This is an example of • C++ program to illustrate • some of its features • */
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  Output operator • cout<<“c++ is a very powerful Object Oriented Programming Language n” ; • Causes the string in quotation marks to be displayed on the screen. • This statement introduces two new C++ features, cout and <<. • The identifier cout (pronounced as C out) is a predefined object that represents the standard output stream in C++. • Here, the standard output stream represents the screen. • The operator << is called the insertion (or put to) operator
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  The iostream File •We have used the following #include directive in the program: • #include <iostream> • The #include directive instructs the compiler to include the contents of the file enclosed within angular brackets into the source file.
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  Namespace • Namespace isa new concept introduced by the ANSI C++ standards committee. • This defines a scope for the identifiers that are used in a program. For using the identifier defined in the namespace scope we must include the using directive, like – Using namespace std; • Here, std is the namespace where ANSI C++ standard class libraries are defined. • All ANSI C++ programs must include this directive. • This will bring all the identifiers defined in std to the current global scope. • Using and namespace are the new keyword of C++.
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  Return Type ofmain() • In C++, main () returns an integer value to the operating system. • Therefore, every main () in C++ should end with a return (0) statement; otherwise a warning an error might occur. • Since main () returns an integer type for main () is explicitly specified as int. • Note that the default return type for all function in C++ is int.
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  Assignment • Discuss thebenefits and applications of object oriented programming • Write a C++ program to print a string “Hello World” on the console output. Briefly Explain the elements of the program.