标签：生成 构造 虚拟 地址 释放 一个 ace let sof
需求：类比数组类，只不过数组类型不再是整型、浮点型等，也可以是类。
1、创建模板类
头文件
#ifndef MYVECTOR_H
#define MYVECTOR_H
#include <iostream>
#include"Teacher.h"
using namespace std;
template <typename T>
class myVector
{
public:
myVector();
void init(int size=0); //构造函数
myVector(const myVector &obj); //拷贝构造函数
~myVector(); //析构函数
const int getLen() const;
const T* getSpace() const {return m_space;}
T& operator [](int index);
myVector<T> &operator =(const myVector<T> &obj);
private:
T *m_space;
int m_len;
};
#endif // MYVECTOR_H
资源文件
#include "myvector.h"
#include"Teacher.h"
template<typename T>
myVector<T>::myVector()
{
m_space = NULL;
m_len = 0;
}
template<typename T>
void myVector<T>::init(int size){
m_space=new T[size];
this->m_len=size;
}
template<typename T>
myVector<T>::myVector(const myVector &obj) //拷贝构造函数
{
m_len=obj.m_len;
cout<<m_len<<endl;
m_space=new T[m_len];
for (int i = 0; i < m_len; ++i) {
m_space[i]=obj.m_space[i];
}
}
template<typename T>
myVector<T>::~myVector() //析构函数
{
cout<<"destory....."<<endl;
if(m_space != NULL){
delete [] m_space;
m_space=NULL;
m_len=0;
}
}
template<typename T>
const int myVector<T>::getLen() const{
return m_len;
}
template<typename T>
T& myVector<T>::operator [](int index)
{
return m_space[index];
}
template<typename T>
myVector<T> & myVector<T>::operator= (const myVector<T> &obj)
{
//先释放旧的内存
if(m_space != NULL){
cout<<"not null"<<endl;
delete[] m_space;
m_space=NULL;
m_len=0;
}
//根据参数分配内存
int length = obj.getLen();
m_space=new T[length];
this->m_len=length;
for (int i = 0; i < m_len; ++i) {
m_space[i]=obj.getSpace()[i];
}
return *this;
}
2、实验类
头文件
#ifndef TEACHER_H
#define TEACHER_H
#include<iostream>
using namespace std;
class Teacher
{
public:
Teacher();
Teacher(char *name,int age);
Teacher(const Teacher &teacher);
~Teacher();
void printTeacher();
friend ostream &operator <<(ostream &out,Teacher &teacher);
Teacher &operator =(const Teacher &teacher);
private:
int age;
char *name;
};
#endif // TEACHER_H
资源文件
#include "Teacher.h"
#include<iostream>
#include<string.h>
using namespace std;
Teacher::Teacher(){
age=0;
name=new char[1];
strcpy(name," ");
}
Teacher::Teacher(char *name, int age){
this->name=new char[strlen(name)];
strcpy(this->name,name);
this->age=age;
}
Teacher::Teacher(const Teacher &teacher){
this->name=new char[strlen(teacher.name)];
strcpy(this->name,teacher.name);
this->age=age;
}
Teacher::~Teacher(){
if(this->name!=NULL){
delete[] this->name;
this->name=NULL;
age==0;
}
}
void Teacher::printTeacher(){
cout<<"Teacher( name: "<<this->name<<" age: "<<this->age<<" )"<<endl;
}
ostream &operator <<(ostream &out,Teacher &teacher){
out<<"Teacher( name: "<<teacher.name<<" age: "<<teacher.age<<" )"<<endl;
return out;
}
Teacher & Teacher::operator =(const Teacher &teacher){
if (this->name != NULL) {
delete[] this->name;
this->name=NULL;
}
this->name=new char[strlen(teacher.name)];
strcpy(this->name,teacher.name);
this->age=teacher.age;
return *this;
}
3、测试函数
主函数
#include "myvector.cpp"
#include"Teacher.h"
int main(){
myVector<int> myv;
myv.init(10);
for (int i = 0; i < myv.getLen(); ++i) {
myv[i] = i+1;
cout<<myv[i]<<" ";
}
cout<<endl;
myVector<int> myv2=myv;
for (int i = 0; i < myv2.getLen(); ++i) {
cout<<myv2[i]<<" ";
}
cout<<endl;
myVector<int> myv3;
myv3=myv;
for (int i = 0; i < myv3.getLen(); ++i) {
cout<<myv3[i]<<" ";
}
Teacher t1("ggg",22),t2("qqq",23),t3("xxx",24);
myVector<Teacher> t;
t.init(3);
t[0]=t1;
t[1]=t2;
t[2]=t3;
cout<<endl;
for (int i = 0; i < 3; ++i) {
cout<<t[i];
}
return 0;
}
注意事项：
在主函数中加入了
#include "myvector.cpp"
问题的根源在于编译器对于模板(template)的编译处理过程中，
大致是这样的(果真如此么？)：
1、模板myVector在编译(compile)期间并未生成具体二进制代码，
在main函数中也没有嵌入这个函数的代码，可能只是包含了一句
call testFunc之类的(稍后详述)
2、编译阶段，在main函数中发现了myVector的引用，但是main.obj中没有相关的
可执行代码（编译器认为该函数在别处定义，这就是为什么需要链接也就是
LINK了，在main中虽然引用到myVector但是只提供了一个call虚拟地址而没有
实际的执行代码）
3、链接阶段，将各个模块(编译期间生成的很多*.obj文件)组织起来
形象的说就是，在LINK的时候把testFunc“嵌入”进来，就像是一个子过程，
在main中从调用处jump到这里即可，执行完毕再跳出子模块，从“中断点”
继续执行后续语句）
4、模板在编译期间是不生成具体代码的。
标签：生成 构造 虚拟 地址 释放 一个 ace let sof
原文地址：https://www.cnblogs.com/helloworldcode/p/9371234.html
