Class 1: Introduction¶

What is Object-oriented Programming¶

computers are not so much machines as they are mind amplification tools and a different kind of expressive medium. As a result, the tools are beginning to look less like machines and more like parts of our minds, and also like other expressive mediums such as writing, painting, sculpture, animation, and filmmaking. **Object-oriented programming is part of this movement toward using the computer as an expressive medium.

Buzzwords of it¶

• responsibility-driven design
• Encapsulation
• Inheritance
• iterators
• overriding
• coupling
• cohesion
• template
• interface
• collection classes
• mutator methods
• Polymorphism

Four main characters of C++¶

• Encapsulation(封装)
• Abstraction(抽象)
• Inheritance(继承)
• Polymorphism(多态)

The First C++ Program¶

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#include <iostream>
using namespace std;

int main()
{
    cout << "Hello, World! I am " << 18 << "Today!" << endl;

    return 0
}

To choose development environment¶

Windows:

• visual studio

Linux, macOS:

• g++, clang, ...(compiler)
• visual studio code(editor)

Read Input¶

How do we read the input in C++? Let's see the example below:

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#include <iostream>
using namespace std;

int main()
{
    cout << "Enter a decimal number: " ;

    int number;
    cin >> number;

    cout << "The number you entered is " << number << " ." << endl;

    return 0;
}

The strengths and weakness of C¶

For C language:

Strengths:

• Efficient programs
• Direct access to machine, suitable for OS and ES
• Flexible

Weakness:

• Insufficient type checking
• Poor support for programming-in-the-large
• Procedure-oriented programming

The relationship between C and C++¶

Actually C is a subset of C++