C++的构造函数属性初始化_静态成员_this指针

//构造函数的属性初始化列表

#define _CRT_SECURE_NO_WARNINGS
#include<stdlib.h>
#include<iostream>
#include<stdarg.h>

using namespace std;

class Teacher {
private:
char *name;
public :
Teacher(char *name) {
this->name = name;
cout << "Teacher有参构造函数" << endl;
}
~Teacher() {
cout << "Teacher析构函数" << endl;
}
char* getName() {
return this->name;
}
};

class Student {
private:
int id;
//属性对象
//Teacher t = Teacher("miss cang");
Teacher t1;
Teacher t2;
public:
Student(int id,char *t1_n,char *t2_n) :t1(t1_n),t2(t2_n) {
this->id = id;
cout << "Student有参构造函数" << endl;
}
void myprint() {
cout << id <<","<<t1.getName()<<","<<t2.getName()<< endl;
}
~Student(){
cout << "Student析构函数" << endl;
}
};

void func() {
Student s1(10,"miss bo","mrs liu");
Student s2(10, "miss zhang", "jason");
s1.myprint();
s2.myprint();
}

void main() {
func();
getchar();
}

//C++ 通过new(delete)动态内存分配
//C malloc (free)

#define _CRT_SECURE_NO_WARNINGS
#include<stdlib.h>
#include<iostream>
#include<stdarg.h>

using namespace std;

class Teacher {
private:
char* name;
public:
Teacher(char* name) {
this->name = name;
cout << "Teacher构造参数" << endl;
}
Teacher() {
cout << "Teacher析构参数" << endl;
}
void setName(char* name) {
this->name = name;
}
char* getName() {
return this->name;
}
};

void func() {
//C++
//会调用构造和析构函数
Teacher *t1 = new Teacher("jack");
cout << t1->getName() << endl;
//释放
delete t1;

//C
//Teacher *t2 = (Teacher*)malloc(sizeof(int)*10);
//t2->setName("jack");
//free(t2);
}

void main() {
func();
//数组类型
//C
//int *p1 = (int*)malloc(sizeof(int)*10);
//p1[0] = 9;
//free(p1);

//C++
int *p2 = new int[10];
p2[0] = 2;
//释放数组[]
delete[] p2;

getchar();
}
//static 静态属性和方法

#define _CRT_SECURE_NO_WARNINGS
#include<stdlib.h>
#include<iostream>
#include<stdarg.h>

using namespace std;

class Teacher {
public :
char* name;
//计数器
static int total;
public :
Teacher(char *name) {
this->name = name;
cout << "Teacher的构造函数"<< endl;
}
~Teacher() {
cout << "Teacher的析构函数" << endl;
}
void setName(char *name) {
this->name = name;
}
char* getName() {
return this->name;
}
static void count() {
total++;
cout << total << endl;
}
};

//静态属性初始化赋值
int Teacher::total = 9;
void main() {
Teacher::total++;
cout << Teacher::total << endl;
//直接通过类名访问
Teacher::count();
//也可以通过对象名访问
Teacher t1("yuehang");
t1.count();
getchar();
}
//类的大小

#define _CRT_SECURE_NO_WARNINGS
#include<stdlib.h>
#include<iostream>
#include<stdarg.h>

using namespace std;

class A
b248
{
public:
int i;
int k;
int j;
static int m;
};

class B {
public :
int i;
int j;
int k;
void myprint() {
cout << "打印" << endl;
}
};

void main() {
cout << sizeof(A) << endl;
cout << sizeof(B) << endl;
// C/C++ 内存分区:栈 堆 全局（静态 全局） 常量区（字符串） 程序代码区
//普通属性与结构体相同的内存布局

//在java中 jvm stack (基本数据类型，对象的引用)
//Native Method stack (本地方法栈)
//方法区

getchar();
}

//this ，当前对象的指针
//函数是共享的，必须要有能够识别当前对象是谁的方法

#define _CRT_SECURE_NO_WARNINGS
#include<stdlib.h>
#include<iostream>
#include<stdarg.h>

using namespace std;

class Teacher {
private:
char *name;
int age;
public :
Teacher(char *name,int age) {
this->name = name;
this->age = age;
cout << "Teacher的构造函数" << endl;
}
~Teacher() {
cout << "Teacher的析构函数" << endl;
}
//常函数，修饰的是this
//既不能改变指针的值，又不能改变指针指向的内容
//const Teacher* const this
void myprintf() const {
printf("%#x\n",this);
//不能改变属性的值
//this->name = "jason";
//不能改变this指针的值
//this = (Teacher*)0x00009;
cout << this->name << "," << this->age << endl;
}
void myprintf2() {
cout << this->name << "," << this->age << endl;
}
};

void main() {
Teacher t1("jack",20);
const Teacher t2("rose",22);
//常量对象只能调用常量函数，不能调用非常量函数
t2.myprintf();
//常函数，当前对象不能被修改，防止数据成员被非法访问
printf("%#x\n",&t1);
t1.myprintf();
printf("%#x\n",&t2);
t2.myprintf();
getchar();
}