6.1指针的引用

#include<iostream>
using namespace std;

struct Teacher
{
	char name[64];
	int age;
};
//在被调用函数去获取一个内存块
int  getTeacher(Teacher **p)
{
	Teacher *tmp = NULL;
	if (p == NULL)
	{
		return -1;
	}
	tmp = (Teacher *)malloc(sizeof(Teacher));
	if (tmp == NULL)
	{
		return -1;
	}
	tmp->age = 33;
	//p是实参的地址，*实参的地址 去间接的修改实参的值 
	*p = tmp;
}


//指针的引用做函数参数---
int  getTeacher2(Teacher* &myp)//理解成int* &tmp
{
	//给myp赋值，相当于给main函数中的pt1赋值
	myp = (Teacher* )malloc(sizeof(Teacher));
	if (myp == NULL)
	{
		return -1;
	}
	myp->age = 36;
}

void FreeTeacher(Teacher *pT1)
{
	if(pT1 == NULL)
	{
		return;
	}
	free(pT1);
}

int main()
{
	//引用的本质   间接赋值的后两个条件ｃ＋＋编译器帮我们做了

	Teacher *pT1 = NULL;

	//1:C语言中的二级指针
	getTeacher(&pT1);

	cout<<"pT1.age:"<<pT1->age<<endl;
	FreeTeacher(pT1) ;

	//c++中指针的引用
	getTeacher2(pT1);
	cout<<"pT1.age:"<<pT1->age<<endl;
	FreeTeacher(pT1);
	system("pause");
	return 0;
}