软硬件系统编程PPT (37).pdf

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1、Object-oriented programming Overview Object Oriented Programming(OOP)is a computer programming architecture A basic principle of OOP is that a computer program is composed of a single unit or object that can function as a subprogram OOP achieves three main goals of software engineering:reusability,f

2、lexibility and scalability OOP=object+class+inheritance+polymorphism+message,the core concept is class and object Class and Object Object-oriented programming takes objects as the core,and the program consists of a series of objects Classes are abstractions of the real world,including data represent

3、ing static attributes and operations on data,and objects are instantiations of classes Objects communicate with each other through messaging to simulate the connection between different entities in the real world In object-oriented programming,objects are the basic modules that make up a program Exa

4、mple of class and object class class person name；/属性 age；ID；Walk（）/行为 Eat（）object P1 “Emily”29 1230099999 Walk（）Eat（）object P2 “John”19 1230098899 Walk（）Eat（）Features-Encapsulation Encapsulation refers to assembling together the data in a computer system and all operating languages related to this d

5、ata(that is,the program code describing the properties of each object and its behavior),and encapsulating them together in an organic entity,that is,in a class data 1 method 1 method 2 data 2 method 1 method 2 data 1 data 2 data 3 function 1 function 2 data 3 method 1 method 2 Features-Inheritance I

6、nheritance is the connection and difference between two or more classes.Refers to the replication or continuation of some unique characteristics and capabilities of one object for another object.That is,a class can be derived from an existing class pet dog bird cat Persian cat Scottish Fold Parrot H

7、usky Labrador Features-Polymorphism Polymorphism refers to allowing objects of different classes to respond to the same message.When multiple different objects receive the same message at the same time,the actions shown are different and have many forms dog cat pet Message:speak()Meow meow Woof woof

8、 Summary Object-oriented programming is to simulate human thinking as much as possible.In this way,the software can be developed more in line with human cognition,and people can use it more smoothly Through the application software can effectively solve the problems in real life.Object-oriented programming makes the problem space describing the problem and the solution space of the problem combined,and as consistent as possible.Ability to transform abstract problems in the objective world into concrete problem objects