核心示例代码

#define _CRT_SECURE_NO_WARNINGS

#include<stdio.h>
#include<string.h>
#include <iostream>

using namespace std;

class Student 
{
public:
    Student() {
        cout<<"构造函数" << endl;
    }

    ~Student() {
        cout << "析构函数" << endl;
    }

    Student(int width,int ptr) {
        cout << "带参构造函数" << endl;
        this->width = width;
        this->ptr = new int(ptr);
    }

    Student(const Student &stu) {
        cout << "拷贝构造函数" << endl;
        this->width = stu.width;
        this->ptr = new int(*stu.ptr);
    }

    void setWidth(int w) {
        this->width = w;
    }

    int getWidth() {
        return this->width;
    }

    void setPtr(int *ptr) {
        this->ptr = new int(*ptr);
    }

    int* getPtr() {
        return this->ptr;
    }

private:
    int width;
    int* ptr;
};

Student getStudent(int width, int ptr) {
    Student stu(width,ptr);//带参构造
    printf("getStudent %p\n",&stu);
    return stu;//拷贝构造
    //函数结束后stu会被回收走析构函数
}

void main() {
    Student *stu1 = new Student();//无参构造
    stu1->setWidth(20);
    int *p = new int(100);
    stu1->setPtr(p);
    Student *stu2 = stu1;//指针赋值，创建副本
    Student stu3 = *stu1;//指针解引用赋值，深拷贝，会调用拷贝构造函数
    cout << "%p:" << stu1 << ", %p:" << stu2 << ",%p:" << &stu3 << endl;
    
    Student stu4 = {20,100};//带参构造
    Student stu5 = stu4;//深拷贝，会调用拷贝构造函数
    cout << "%p:" << &stu4 << ",%p:" << &stu5<< endl;

    Student stu6;//无参构造
    stu6 = stu4;//默认调用=赋值操作符
    cout << "%p:" << &stu6<<endl;
    getStudent(2,3);
    getchar();
    //整个main结束，getStudent()返回的Student再次被回收，走析构函数
}

运行结果

构造函数
拷贝构造函数
%p:01223508, %p:01223508,%p:00EFFCC0
带参构造函数
拷贝构造函数
%p:00EFFCB0,%p:00EFFCA0
构造函数
%p:00EFFC90
带参构造函数
getStudent 00EFFB54
拷贝构造函数
析构函数
析构函数