typedef struct Teacher
{
	char name[64];
	int age;
	char* pname2;//结构体里套用指针
}Teacher;


void copyTeacher(Teacher* to, Teacher* from)
{
	//*to = *from;
	memcpy(to, from, sizeof(Teacher));//完成一次copy 同理t2释放内存
}
void main()
{
	Teacher t1;
	Teacher t2;


	strcpy(t1.name, "name1");
	t1.pname2 = (char*)malloc(100);
	strcpy(t1.pname2, "ssss");
	//t1 copy t2
	copyTeacher(&t2, &t1);
	if (t1.pname2 != NULL)
	{
		free(t1.pname2);
		t1.pname2 = NULL;
	}

	if (t2.pname2 != NULL)
	{
		free(t2.pname2);//触发断点
		t2.pname2 = NULL;
	}
}

两个指针变量指向同一个内存空间 编译器的=操作只会copy指针的值不会copy指针指向的内存数据 从from 拷贝到to

typedef struct Teacher
{
	char name[64];
	int age;
	char* pname2;//结构体里套用指针
}Teacher;


void copyTeacher(Teacher* to, Teacher* from)
{
	*to = *from;//把指针变量copy过去
	//memcpy(to, from, sizeof(Teacher));//完成一次copy 同理t2释放内存
	to->pname2 = (char*)malloc(100);//copy数据过去
	strcpy(to->pname2, from->pname2);//显示内存空间则可以释放了两次
}
void main()
{
	Teacher t1;
	Teacher t2;


	strcpy(t1.name, "name1");
	t1.pname2 = (char*)malloc(100);
	strcpy(t1.pname2, "ssss");
	//t1 copy t2
	copyTeacher(&t2, &t1);
	if (t1.pname2 != NULL)
	{
		free(t1.pname2);
		t1.pname2 = NULL;
	}

	if (t2.pname2 != NULL)
	{
		free(t2.pname2);//触发断点
		t2.pname2 = NULL;
	}
}