C++多態實例

#include <iostream> #include <string> 
using namespace std; //class 實現 
class Employee { string name; public: Employee(string n); virtual void print(); }; //class 成員函數實現 
Employee::Employee(string n) :name(n)//初始化成員列表 
{ //name = n; 
} void Employee::print() { cout << name << endl; } //class 實現 
class Manager: public Employee { int level; public: Manager(string n, int l = 1); //virtual void print(); 
    void print(); }; //class 成員函數實現 
Manager::Manager(string n, int l) :Employee(n), level(l) { } void Manager::print() { cout << level << "\t"; Employee::print(); } ////派生類的構造函數只能描述它自己的成員和其直接基類的初始式，不能去初始化基類的成員。 
//Manager::Manager(string n, int l) : name(n), level(l) //{ //}


int main() { // Manager m("Zhang",2); // Employee e("Li"); // m.print(); // e.print(); //    
// cout<<"ok-----------"<<endl; //    
// Employee *p=&e; // p->print(); // cout<<"ok-2222----------"<<endl; //    
// p=&m; // p->print(); //    
// cout<<"ooo"<<endl; //    
// Manager *q=&m; // q->print(); // Employee *employees[100]; // int num = 0; //    
// employees[num] = &e; // num++; // employees[num] = &m; // num++;

    ///////////////////////////////////////////
 Employee* employees[100]; int e_num = 0; Employee* pe; string name; int level; char cmd; cout << "input cmd" << endl; while (cin >> cmd) { if (cmd == 'M' || cmd == 'm') { cout << "input name and level" << endl; cin >> name >> level; pe = new Manager(name, level); employees[e_num] = pe; e_num++; } else if (cmd == 'e' || cmd == 'E') { cout << "input name" << endl; cin >> name; pe = new Employee(name); employees[e_num] = pe; e_num++; } else 
            break; cout << "input cmd" << endl; } for (int i = 0; i < e_num; i++) { employees[i]->print(); } return 0; }

 

input cmd
M
input name and level
li 3
input cmd
m
input name and level
rr
4
input cmd
e
input name
bffd
input cmd
e
input name
sdfsdfsdf
input cmd
s
3 li
4 rr
bffd
sdfsdfsdf

通過基類指針Employee *pe可以指向基類和派生類。從而達到多態的效果。后面s后的就是輸出的結果。