带参构造

代码

Student.h

#ifndef STUDENT_H
#define STUDENT_H

#include <iostream>

using namespace std;

class Student
{
    public:
        //构造函数的重载与普通函数的重载规则相同
        //重载时不关注返回值类型，只关注参数类型
        //如果构造函数中，只有一个是带唯一的参数：Student student4 = 40;
        Student();

        Student(string,string);//带参构造
        Student(int);

        ~Student();

        void ShowInfo();

        string GetName() {
            return m_Name;
        }

        void SetName(string val) {
            m_Name = val;
        }

        string Getdesc() {
            return m_desc;
        }

        void Setdesc(string val) {
            m_desc = val;
        }

        int Getage() {
            return m_age;
        }

        void Setage(int val) {
            if(val<0){
                m_age = 18;
            }else{
                m_age = val;
            }
        }

    protected:

    private:
        string m_Name;
        string m_desc;
        int m_age;
};

#endif // STUDENT_H

Student.cpp

#include "Student.h"

Student::Student()
{
    cout<<"默认构造"<<endl;
}

//Student::Student(string name,string desc){
//    cout<<"带参构造：Student(string name,string desc)"<<endl;
//
//    m_Name = name;//等价写法：SetName(name);
//
//    m_desc = desc;//等价写法：Setdesc(desc);
//}

Student::Student(string name,string desc):m_Name(name),m_desc(desc)//初始化参数列表写法，列表顺序与定义顺序无关
{
    cout<<"带参构造：Student(string name,string desc)"<<endl;
}

Student::Student(int age){
    cout<<"带参构造：Student(int age)"<<endl;
    Setage(age);
}

void Student::ShowInfo(){
    cout<<m_Name<<"  "<<m_desc<<endl;
}

Student::~Student()
{
    //dtor
}

main.cpp

#include <iostream>
#include "Student.h"

using namespace std;

int main()
{
    cout<<"student1"<<endl;
    Student student1;//直接调用默认构造。在栈内存中直接分配空间

    cout<<endl<<"student2"<<endl;
    Student student2("马云","一无所有杰克马");
    student2.ShowInfo();

    cout<<endl<<"student3 4"<<endl;
    Student student3(40);
    Student student4 = 40;//与student3结果相同

    //Student student1 可以直接使用类和对象，方法一
    //方法二
    cout<<endl<<"student5"<<endl;
    Student * student5 = new Student("马化腾","普通家庭");//Student 指针类型。分配内存的同时调用构造函数
    student5->ShowInfo();//指针访问属性或者方法要用 ->
    return 0;
}

运行结果