C++ has three object-oriented features: encapsulation, inheritance, and polymorphism.
C++ believes that everything in the world is an object, and each object has attributes and behaviors .
Objects with the same attributes are abstracted as classes.
4.1 Package:
4.1.1 Significance of Package
1. Take attributes and behaviors as a whole;
2. Permission control of attributes and behaviors
Attribute, behavior
#include<iostream>
#include<string>
using namespace std;
class student
{
//属性和行为统称为 成员
//属性：又称为 成员属性 成员变量
//行为：又称为 成员函数 成员方法
public:
//属性
string name;
string xvehao;
//行为
void print()
{
cout << "姓名：" << name << " 学号：" << xvehao << endl;
}
void setname(string thename)
{
name = thename;
}
void setxvehao(string thexvehao)
{
xvehao = thexvehao;
}
};
int main()
{
string name;
string xvehao;
cout << "请输入姓名：" << endl;
cin >> name;
cout << "请输入学号：" << endl;
cin >> xvehao;
student stu1;//创建一个学生，实例化对象
//stu1.name = name;
stu1.setname(name);
//stu1.xvehao = xvehao;
stu1.setxvehao(xvehao);
stu1.print();
system("pause");
return 0;
}Access rights: public, protected, private.
4.1.2 The difference between struct and class
The only difference between struct and class is that by default , struct is a public authority and class is a private authority.
4.1.3 Set member properties to private
#include<iostream>
#include<string>
using namespace std;
class person
{
public://通过公共权限控制访问权限
//写姓名
void setname(string thename)
{
name = thename;
}
//读姓名
string readname()
{
return name;
}
void setage(int theage)//写权限，检验数据有效性
{
if (theage < 0 || theage>150)
{
cout << "输入年龄有误" << endl;
}
else
{
age = theage;
}
}
int readage()
{
//age = 0;
return age;
}
void setid(string theid)
{
id = theid;
}
private://属性设置为私有
string name;
int age;
string id;
};
int main()
{
person p;
p.setname("li");
cout << "姓名为：" << p.readname() << endl;
p.setage(12);
cout << "年龄：" << p.readage() << endl;
p.setid("1111");
system("pause");
return 0;
}