面向对象C++ 学生类1

类内声明，类外定义

使用类内的成员函数给类内的私有成员赋值，并且成员函数在类内声明，类外定义

#include <iostream> 
#include <string.h>
using namespace std;
class Student
{
    private:
        string name;
        string sex;
        float math;
        float chinese;
    public:
        float average;
        void setname();
        void setmath();
        void setchinese();
        void setsex();
        void show_data ();
        float show_average();
        float show_sum() ;
};  
void Student::setsex()
{
    cin>>sex;
}  
void Student::setname ()
{
    cin>>name;
}
void Student::setmath ()
{
    cin>>math;
}
void Student::setchinese ()
{
    cin>>chinese;
}
float Student::show_average ()
{
    cout<<"平均分："<<(math+chinese)/2<<endl;
}
float Student::show_sum ()
{
    cout<<"总分："<<math + chinese<<endl;
}
void Student::show_data()
{
    cout<<"学生姓名："<<name<<endl;
    cout<<"学生性别："<<sex<<endl; 
    cout<<"数学："<<math<<endl;
    cout<<"语文：" <<chinese<<endl; 
}

main()
{
    Student a;
    a.setname();
    a.setsex();
    a.setmath();
    a.setchinese();
    a.show_data();
    a.show_average();
    a.show_sum();
    return 0;
}

 

 构造函数初始化

 使用构造函数给类内的私有变量赋值，并输出学生信息

 

#include <iostream> 
#include <string.h>
using namespace std;
class Student
{
    private:
        string name;
        string sex;
        float math;
        float chinese;
     public:
         Student (string,string,float,float);
         void show_data ();
         float show_average();
         float show_sum() ;
};
            
Student::Student (string a,string b,float c,float d)
{    
    this->name=a;
    this->sex=b;
    math=c;
    chinese=d;
}
void Student::show_data()
{
    cout<<"学生姓名："<<name<<endl;
    cout<<"学生性别："<<sex<<endl;
    cout<<"数学："<<math<<endl;
    cout<<"语文：" <<chinese<<endl;
}
float Student::show_average ()
{
    cout<<"平均分："<<(math+chinese)/2<<endl;
}
float Student::show_sum()
{
    cout<<"总分："<<math + chinese<<endl;
}

main()
{ 
    string a,b;
    float c,d;
    cin>>a>>b>>c>>d;
    Student t(a,b,c,d);
    t.show_data ();
    t.show_average();
    t.show_sum();
    return 0;
}