前言
前面介绍到了C++的泛型编程,并实现了万能容器,不过那使用的是数组,今天呢咱带大家实践一下使用泛型技术,结合单链表实现一个职工管理系统。保证大家看完之后有所感悟。
一、泛型编程思想
所谓泛型就是类型不固定,只需修改少量代码就可以扩展为其他类型的应用,由于C++是一门静态编译型的语言，变量的类型都是事先编译好的,如果不用泛型进行编程,一段代码始终就是那么点作用。使用泛型编程后，可以很简单的对其他类型进行扩展。泛型编程核心思想就是将数据类型设置为模板,第一次编译是对模板进行编译,第二次编译会带入人为传的类型参数。前面文章有讲函数模板与类模板,忘记的小伙伴可以去看看。
二、单链表是什么?
单链表中的单代表一条,链表意思就是一个个节点链接起来的表结构。 其最典型的特征就是节点只有一个指针域。并且该指针域指向下一节点的地址
1.图示
链表中的第一个节点被称为头结点,一般不存储数据,指向头结点的指针称为头指针 第一个存储数据的节点称为首节点,末尾节点称为尾节点,指针域赋空,防止变为野指针。
2.链表的节点结构【节点类】
①常规链表节点
包含数据域,指针域。指针域指针类型与节点类型保持一致。
class node { private: //数据域 string data1; string data2; //指针域 node* next; public: node() { } }
②泛型链表节点
其中T代表的是一种不确定的数据类型,data是一个T类型的对象,其作用类似于结构体 存储数据域的信息,但是在c++中他必须用类实现,因为该数据类型要有属于自己的属性 与方法。node<T>* next代表一个T类型的node指针,其本质还是node指针，只不过 T的类型决定着node *指向的节点中的data的类型。
代码如下：
template<typename T> class node { private: //数据域 T data; //指针域 node<T>* next; public: node() { } }
3.链表类
常规链表类中需要包含一个头指针,指向链表的头结点，然后创建一个链表对其增删改查 泛型编程中的链表类，也要是一个链表类。实现类型的参数化,具体如下：
template<typename T> class link { private: //传入类型的时候,先传给link然后link会传给node; node<T>* head; public: link() { } bool add(){ } bool del(){ } 。。。
三、泛型编程核心
1.实现数据类
泛型就是要将你写的类型,像对待int string类型那样对待。首先要进行的就是运算符重载 重载了运算符你可以使用cin,cout直接对相应的对象进行输入，输出。可以直接使用=进行赋值。 具体实现如下：
class officer { //重载了标准输入输出流函数、文件输入输出流函数（可以直接存文件） friend ostream& operator<<(ostream& out, officer& obj); friend istream& operator>>(istream& in, officer& obj); friend ofstream& operator<<(ofstream& outfile, officer& obj);//--------输出到文件 friend ifstream& operator>>(ifstream& infile, officer& obj);//---------读取文件 private: string id_card; string name; string sex; int age; string post; int money; public://---------------------------------私有属性管理方法 officer() { id_card = ""; name = ""; sex = ""; age = 0; post = ""; money = 0; } //拷贝构造函数结合赋值函数,直接进行赋值。 officer(officer& obj) { this->id_card = obj.getid(); this->name = obj.getname(); this->sex = obj.getsex(); this->age = obj.getage(); this->money = obj.getmoney(); this->post = obj.getpost(); } officer& operator=(officer& obj) { this->id_card = obj.getid(); this->name = obj.getname(); this->sex = obj.getsex(); this->age = obj.getage(); this->money = obj.getmoney(); this->post = obj.getpost(); return *this; } //查重时使用 bool operator==(officer& obj) { if (this->getid() == obj.getid() && this->getname() == obj.getname() && this->getsex() == obj.getsex()\ && this->getage() == obj.getage() && this->getpost() == obj.getpost() && this->getmoney() == obj.getmoney()) { return true; } return false; } bool operator!=(officer& obj) { if (this->getid() == obj.getid()) { return false; } return true; } //排序时使用,根据工资的高低。 bool operator>(officer& obj) { if (this->getmoney() > obj.getmoney()) { return true; } return false; } bool operator<(officer& obj) { if (this->getmoney() < obj.getmoney()) { return true; } return false; } void setpost(string post) { this->post = post; } void setmoney(int money) { this->money = money; } void setid(string id) { id_card = id; } void setname(string name) { this->name = name; } void setsex(string sex) { this->sex = sex; } void setage(int age) { this->age = age; } string getid() { return id_card; } string getname() { return name; } string getsex() { return sex; } int getage() { return age; } string getpost() { return post; } int getmoney() { return money; } };
2.实现链表类
泛型的链表类、节点类一般就是写死的,做到换一个数据类还可以用的效果 所以在泛型链表类中的提示性语句要有一定的泛化程度,不可以针对某种类型提示。
template<typename T> class link { private: node<T>* head; public: link() { string classname; ifstream infile; node<T>* p, * q; p = new node<T>; p->setnext(NULL); head = new node<T>; head->setnext(NULL); q = head; classname = head->GetClass(); classname.erase(remove(classname.begin(), classname.end(), '<'), classname.end()); classname.erase(remove(classname.begin(), classname.end(), '>'), classname.end()); //cout << classname << endl; infile.open(classname); while (infile >> p->opedata()) { q->setnext(p); q = q->getnext(); p = new node<T>; p->setnext(NULL); } delete p; infile.close(); } void addnode() {//-------------------------增 node<T>* p, * q; p = new node<T>; p->setnext(NULL); cout << "请输入您要存储的数据:" << endl; cin >> p->opedata(); q = head; for (; q->getnext() != NULL; q = q->getnext()) { if (q->getnext()->opedata() == p->opedata()) { cout << "您输入的数据,已存在,不需要重复录入" << endl; system("pause"); delete p; return; } } q->setnext(p); savelink(); cout << "存储成功！" << endl; system("pause"); } void delnode() {//---------------------------删 bool k = false; node<T>* p, * q, * r; p = new node<T>; p->setnext(NULL); cout << "请输入您要删除的数据" << endl; cin >> p->opedata(); q = head; for (; q->getnext() != NULL; q = q->getnext()) { if (q->getnext()->opedata() == p->opedata() && q->getnext()->getnext() != NULL) { r = q->getnext(); q->getnext() = q->getnext()->getnext(); delete r; k = true; break; } else if (q->getnext()->opedata() == p->opedata() && q->getnext()->getnext() == NULL) { r = q->getnext(); delete r; q->setnext(NULL); k = true; break; } } if (k == false) { cout << "没有找到您要删除的数据,请核实后再来！" << endl; } else if (k == true) { savelink(); cout << "删除成功！" << endl; } delete p; system("pause"); return; } void altenode() {//-------------------------------改 int judgecin = 0; bool k = false; node<T>* p, * q, * r; p = new node<T>; p->setnext(NULL); cout << "请输入您要改动的数据" << endl; judgecin = 1; cin >> p->opedata(); judgecin = 0; q = head; for (; q->getnext() != NULL; q = q->getnext()) { if (q->getnext()->opedata() == p->opedata()) { cout << "请输入新的数据:" << endl; rewrite: cin >> p->opedata(); for (r = head; r->getnext() != NULL; r = r->getnext()) { if (r->getnext()->opedata() == p->opedata() && p->opedata() != q->getnext()->opedata()) { system("cls"); judgecin++; if (judgecin == 3) { cout << "您多次输入信息错误,请核实后再来,将要返回主菜单" << endl; delete p; system("pause"); return; } cout << "请输入您自己的身份信息！或输入新的身份证号" << endl; goto rewrite; } } q->getnext()->opedata() = p->opedata(); k = true; } } if (k == true) { savelink(); cout << "修改成功！" << endl; } else { cout << "修改失败!没有找到该数据！" << endl; } delete p; system("pause"); return; } void selnode() {//----------------------------------查 cout << "请输入您要查找的数据" << endl; bool k = false; node<T>* p, * q; p = new node<T>; p->setnext(NULL); cin >> p->opedata(); for (q = head; q->getnext() != NULL; q = q->getnext()) { if (q->getnext()->opedata() == p->opedata()) { k = true; cout << "您要查找的数据如下！" << endl; cout << q->getnext()->opedata() << endl; //break; } } if (k == false) { cout << "没有找到您要查找的数据！抱歉" << endl; } system("pause"); return; } void printlink() {//------------------------------打印链表 node<T>* p; sortlink(); for (p = head; p->getnext() != NULL; p = p->getnext()) { cout << p->getnext()->opedata() << endl; } system("pause"); } void sortlink() {//-------------------------------排序 node<T>* p, * q; if (head->getnext() == NULL) { cout << "没有数据,无需排序!" << endl; return; } if (head->getnext()->getnext() == NULL) { cout << "一组数据,无需排序!" << endl; return; } for (p = head->getnext(); p->getnext() != NULL; p = p->getnext()) { for (q = p->getnext(); q != NULL; q = q->getnext()) { if (q->opedata() > p->opedata()) { node<T> temp; temp = *q; *q = *p; *p = temp; temp.getnext() = q->getnext(); q->getnext() = p->getnext(); p->getnext() = temp.getnext(); } } } } void savelink() {//--------------------------------------存链表 ofstream outfile; string classname; node<T>* p; p = head; classname = head->GetClass(); classname.erase(remove(classname.begin(), classname.end(), '<'), classname.end()); classname.erase(remove(classname.begin(), classname.end(), '>'), classname.end()); outfile.open(classname); while (p->getnext() != NULL) { p = p->getnext(); outfile << p->opedata() << endl; } outfile.close(); } ~link() {//--------------------------------------------销毁链表 node<T>* p; p = head->getnext(); while (p != NULL) { delete head; head = p; p = p->getnext(); } }// };
四、运行截图
1.主菜单
2.查看信息
3.更换数据类型
将officer类型注释掉，使用int类型
4.再次显示所有信息【抛转】
可以看到就算将officer类型换为int类型,程序依旧可以稳定的运行。 这里打印职工信息系统的提示性语句出现到了这里,如果大家真的理解了泛型的思想 肯定可以轻而易举的改掉这处不足,有什么想法的小伙伴评论区留言博主吧。
五、源码
#include<fstream> #include<iostream> using namespace std; #include<windows.h> #include<conio.h> char off_menu(); class officer; int mynum(string str) {//-----------------判断字符串是否全为数字 for (unsigned int i = 0; i < str.length(); i++) { if (!isdigit(str[i])) { return 1; } } return 0; } template<typename T> class node { private: T data; node<T>* next; public: node() { } void setnext(node<T>* p) { if (p != NULL) { next = new node<T>; next->data = p->opedata(); next->next = p->getnext(); } else next = p; } T& opedata() { return data; } node<T>*& getnext() { return next; } const char* GetClass() { return typeid(*this).name(); } }; template<typename T> class link { private: node<T>* head; public: link() { string classname; ifstream infile; node<T>* p, * q; p = new node<T>; p->setnext(NULL); head = new node<T>; head->setnext(NULL); q = head; classname = head->GetClass(); classname.erase(remove(classname.begin(), classname.end(), '<'), classname.end()); classname.erase(remove(classname.begin(), classname.end(), '>'), classname.end()); //cout << classname << endl; infile.open(classname); while (infile >> p->opedata()) { q->setnext(p); q = q->getnext(); p = new node<T>; p->setnext(NULL); } delete p; infile.close(); } void addnode() {//-------------------------增 node<T>* p, * q; p = new node<T>; p->setnext(NULL); cout << "请输入您要存储的数据:" << endl; cin >> p->opedata(); q = head; for (; q->getnext() != NULL; q = q->getnext()) { if (q->getnext()->opedata() == p->opedata()) { cout << "您输入的数据,已存在,不需要重复录入" << endl; system("pause"); delete p; return; } } q->setnext(p); savelink(); cout << "存储成功！" << endl; system("pause"); } void delnode() {//---------------------------删 bool k = false; node<T>* p, * q, * r; p = new node<T>; p->setnext(NULL); cout << "请输入您要删除的数据" << endl; cin >> p->opedata(); q = head; for (; q->getnext() != NULL; q = q->getnext()) { if (q->getnext()->opedata() == p->opedata() && q->getnext()->getnext() != NULL) { r = q->getnext(); q->getnext() = q->getnext()->getnext(); delete r; k = true; break; } else if (q->getnext()->opedata() == p->opedata() && q->getnext()->getnext() == NULL) { r = q->getnext(); delete r; q->setnext(NULL); k = true; break; } } if (k == false) { cout << "没有找到您要删除的数据,请核实后再来！" << endl; } else if (k == true) { savelink(); cout << "删除成功！" << endl; } delete p; system("pause"); return; } void altenode() {//-------------------------------改 int judgecin = 0; bool k = false; node<T>* p, * q, * r; p = new node<T>; p->setnext(NULL); cout << "请输入您要改动的数据" << endl; judgecin = 1; cin >> p->opedata(); judgecin = 0; q = head; for (; q->getnext() != NULL; q = q->getnext()) { if (q->getnext()->opedata() == p->opedata()) { cout << "请输入新的数据:" << endl; rewrite: cin >> p->opedata(); for (r = head; r->getnext() != NULL; r = r->getnext()) { if (r->getnext()->opedata() == p->opedata() && p->opedata() != q->getnext()->opedata()) { system("cls"); judgecin++; if (judgecin == 3) { cout << "您多次输入信息错误,请核实后再来,将要返回主菜单" << endl; delete p; system("pause"); return; } cout << "请输入您自己的身份信息！或输入新的身份证号" << endl; goto rewrite; } } q->getnext()->opedata() = p->opedata(); k = true; } } if (k == true) { savelink(); cout << "修改成功！" << endl; } else { cout << "修改失败!没有找到该数据！" << endl; } delete p; system("pause"); return; } void selnode() {//----------------------------------查 cout << "请输入您要查找的数据" << endl; bool k = false; node<T>* p, * q; p = new node<T>; p->setnext(NULL); cin >> p->opedata(); for (q = head; q->getnext() != NULL; q = q->getnext()) { if (q->getnext()->opedata() == p->opedata()) { k = true; cout << "您要查找的数据如下！" << endl; cout << q->getnext()->opedata() << endl; //break; } } if (k == false) { cout << "没有找到您要查找的数据！抱歉" << endl; } system("pause"); return; } void printlink() {//------------------------------打印链表 node<T>* p; sortlink(); for (p = head; p->getnext() != NULL; p = p->getnext()) { cout << p->getnext()->opedata() << endl; } system("pause"); } void sortlink() {//-------------------------------排序 node<T>* p, * q; if (head->getnext() == NULL) { cout << "没有数据,无需排序!" << endl; return; } if (head->getnext()->getnext() == NULL) { cout << "一组数据,无需排序!" << endl; return; } for (p = head->getnext(); p->getnext() != NULL; p = p->getnext()) { for (q = p->getnext(); q != NULL; q = q->getnext()) { if (q->opedata() > p->opedata()) { node<T> temp; temp = *q; *q = *p; *p = temp; temp.getnext() = q->getnext(); q->getnext() = p->getnext(); p->getnext() = temp.getnext(); } } } } void savelink() {//--------------------------------------存链表 ofstream outfile; string classname; node<T>* p; p = head; classname = head->GetClass(); classname.erase(remove(classname.begin(), classname.end(), '<'), classname.end()); classname.erase(remove(classname.begin(), classname.end(), '>'), classname.end()); outfile.open(classname); while (p->getnext() != NULL) { p = p->getnext(); outfile << p->opedata() << endl; } outfile.close(); } ~link() {//--------------------------------------------销毁链表 node<T>* p; p = head->getnext(); while (p != NULL) { delete head; head = p; p = p->getnext(); } }// }; class officer { friend ostream& operator<<(ostream& out, officer& obj); friend istream& operator>>(istream& in, officer& obj); friend ofstream& operator<<(ofstream& outfile, officer& obj);//--------输出到文件 friend ifstream& operator>>(ifstream& infile, officer& obj);//---------读取文件 private: string id_card; string name; string sex; int age; string post; int money; public://---------------------------------私有属性管理方法 officer() { id_card = ""; name = ""; sex = ""; age = 0; post = ""; money = 0; } officer(officer& obj) { this->id_card = obj.getid(); this->name = obj.getname(); this->sex = obj.getsex(); this->age = obj.getage(); this->money = obj.getmoney(); this->post = obj.getpost(); } officer& operator=(officer& obj) { this->id_card = obj.getid(); this->name = obj.getname(); this->sex = obj.getsex(); this->age = obj.getage(); this->money = obj.getmoney(); this->post = obj.getpost(); return *this; } bool operator==(officer& obj) { if (this->getid() == obj.getid() && this->getname() == obj.getname() && this->getsex() == obj.getsex()\ && this->getage() == obj.getage() && this->getpost() == obj.getpost() && this->getmoney() == obj.getmoney()) { return true; } return false; } bool operator!=(officer& obj) { if (this->getid() == obj.getid()) { return false; } return true; } bool operator>(officer& obj) { if (this->getmoney() > obj.getmoney()) { return true; } return false; } bool operator<(officer& obj) { if (this->getmoney() < obj.getmoney()) { return true; } return false; } void setpost(string post) { this->post = post; } void setmoney(int money) { this->money = money; } void setid(string id) { id_card = id; } void setname(string name) { this->name = name; } void setsex(string sex) { this->sex = sex; } void setage(int age) { this->age = age; } string getid() { return id_card; } string getname() { return name; } string getsex() { return sex; } int getage() { return age; } string getpost() { return post; } int getmoney() { return money; } }; ostream& operator<<(ostream& out, officer& obj) { out << obj.getid() << "\t"; out << obj.getname() << "\t"; out << obj.getsex() << "\t"; out << obj.getage() << "\t"; out << obj.getpost() << "\t"; out << obj.getmoney() << "\t"; // cout << endl; return out; } istream& operator>>(istream& in, officer& obj) { cout << "身份证(18位):"; id_here: in >> obj.id_card; if (obj.getid() == "00") { return in; } else if (obj.getid().length() != 18) { cout << "输入格式不规范请重新输入:"; goto id_here; } //if (judgecin == 1) { // return in; //} cout << "姓名:"; in >> obj.name; cout << "性别:"; sex_here: in >> obj.sex; if (obj.getid() == "00") { return in; } else if (obj.getsex() != "男" && obj.getsex() != "女") { cout << "请输入准确的性别:"; goto sex_here; } cout << "年龄:"; string age; age_here: in >> age; if (obj.getid() == "00") { return in; } else if (mynum(age) || age.length() > 3) { cout << "输入不规范请重新输入:"; goto age_here; } obj.age = atoi(age.c_str()); cout << "职位:"; post_here: in >> obj.post; if (obj.getid() == "00") { return in; } else if (obj.getpost() != "监狱长" && obj.getpost() != "探长" && \ obj.getpost() != "参谋长" && obj.getpost() != "大警司" && obj.getpost() != "小警司") { cout << "请输入职位(监狱长,探长,参谋长,大警司,小警司):"; goto post_here; } if (obj.getpost() == "监狱长") { obj.money = 30000; } else if (obj.getpost() == "探长") { obj.money = 24000; } else if (obj.getpost() == "参谋长") { obj.money = 24500; } else if (obj.getpost() == "大警司") { obj.money = 20000; } else if (obj.getpost() == "小警司") { obj.money = 18000; } return in; } ofstream& operator<<(ofstream& outfile, officer& obj) { outfile << obj.getid() << " " << obj.getname() << " " << obj.getsex() << " " << obj.getage()\ << " " << obj.getpost() << " " << obj.getmoney();// << endl; return outfile; } ifstream& operator>>(ifstream& infile, officer& obj) { string post1; int money1; string id1; string name1; string sex1; int age1; infile >> id1 >> name1 >> sex1 >> age1 >> post1 >> money1; obj.setid(id1); obj.setname(name1); obj.setsex(sex1); obj.setage(age1); obj.setpost(post1); obj.setmoney(money1); return infile; } int main() { //link<officer> myarray; link<int> myarray; char menun; while (1) { menun = off_menu(); if (menun == '1') { system("cls"); int len; cout << "请输入您要增加节点的个数:"; cin >> len; for (int i = 0; i < len; i++) { myarray.addnode(); system("cls"); } } else if (menun == '2') { myarray.delnode(); } else if (menun == '3') { myarray.altenode(); } else if (menun == '4') { myarray.selnode(); } else if (menun == '5') { cout << "身份证\t\t\t姓名\t性别\t年龄\t职位\t工资" << endl; myarray.printlink(); } else if (menun == '6') { break; } system("cls"); } return 0; } char off_menu() { char n; n = '0'; system("cls"); cout << "\n\n\n"; cout << "\t\t\t\t\t-------欢迎使用本信息管理系统-------" << endl; cout << "\t\t\t\t\t*\t \t\t\t *" << endl; cout << "\t\t\t\t\t*\t 1.录入员工信息\t *" << endl; cout << "\t\t\t\t\t*\t \t\t\t *" << endl; cout << "\t\t\t\t\t*\t 2.删除员工信息\t *" << endl; cout << "\t\t\t\t\t*\t \t\t\t *" << endl; cout << "\t\t\t\t\t*\t 3.修改员工信息\t *" << endl; cout << "\t\t\t\t\t*\t \t\t\t *" << endl; cout << "\t\t\t\t\t*\t 4.查询员工信息\t *" << endl; cout << "\t\t\t\t\t*\t \t\t\t *" << endl; cout << "\t\t\t\t\t*\t 5.查看员工信息\t *" << endl; cout << "\t\t\t\t\t*\t \t\t\t *" << endl; cout << "\t\t\t\t\t*\t 6.退出该系统\t\t *" << endl; cout << "\t\t\t\t\t*\t \t\t\t *" << endl; cout << "\t\t\t\t\t------------------------------------" << endl; cout << "———————————————————————————————————————————————————————----------" << endl; cout << "———————————————————————————————————————————————————————----------" << endl; cout << "please your choose:"; while (1) { n = _getch(); if (n >= '1' && n <= '6') { break; } } cout << endl; return n; }
总结
理解了泛型会对python等解释性语言有更好的理解。希望大家能够好好理解这个项目,在博主的基础之上更上一层楼。如果大家有什么好的想法请评论区留言博主吧。觉着不错的欢迎大家点赞收藏。(^_−)☆
