实验五 继承和多态
实验任务3：
task3.cpp和pets.hpp的源码，运行测试结果如下
#pragma once #include<iostream> #include<string> #include<iomanip> using namespace std; class MachinePets{ private: string nickname; public: MachinePets(const string &s):nickname{s}{} virtual string talk()const=0; string get_nickname()const{ return nickname; } }; class PetCats:public MachinePets{ public: PetCats(const string &s):MachinePets{s}{ } string talk()const override; }; string PetCats::talk()const{ return "miao"; } class PetDogs:public MachinePets{ public: PetDogs(const string &s):MachinePets{s}{ } string talk()const override; }; string PetDogs::talk()const{ return "wang"; }
#include <iostream> #include <vector> #include "pets.hpp" void test() { using namespace std; vector<MachinePets *> pets; pets.push_back(new PetCats("miku")); pets.push_back(new PetDogs("da huang")); for(auto &ptr: pets) cout <<ptr->get_nickname() << " says " << ptr->talk() << endl; } int main() { test(); }
实验任务4：
task4.cpp和film.hpp的源码，运行测试结果如下
#pragma once #include<iostream> #include<iomanip> #include<string> using namespace std; class Film { private: string name; string director; string area; string time; public: Film(const string &name="",const string &director="",const string &area="",const string &time=""); friend ostream& operator<<(ostream& out, const Film& f); friend istream& operator>>(istream& in, Film& f); string get_year()const { return time; } }; Film::Film(const string &name,const string &director,const string &area,const string &time){ this->name=name; this->director=director; this->area=area; this->time=time; } ostream& operator<<(ostream& out, const Film& f) { out << f.name<< setw(15) << f.director <<setw(10) << f.area << setw(10) << f.time << endl; return out; } istream& operator>>(istream& in, Film& f) { in >> f.name >> f.director >> f.area >> f.time; return in; } bool compare_by_year(const Film& f1, const Film& f2) { return f1.get_year() < f2.get_year(); }
#pragma once #include<iostream> #include<iomanip> #include<string> using namespace std; class Film { private: string name; string director; string area; string time; public: Film(const string &name="",const string &director="",const string &area="",const string &time=""); friend ostream& operator<<(ostream& out, const Film& f); friend istream& operator>>(istream& in, Film& f); string get_year()const { return time; } }; Film::Film(const string &name,const string &director,const string &area,const string &time){ this->name=name; this->director=director; this->area=area; this->time=time; } ostream& operator<<(ostream& out, const Film& f) { out << f.name<< setw(15) << f.director <<setw(10) << f.area << setw(10) << f.time << endl; return out; } istream& operator>>(istream& in, Film& f) { in >> f.name >> f.director >> f.area >> f.time; return in; } bool compare_by_year(const Film& f1, const Film& f2) { return f1.get_year() < f2.get_year(); } task4.cpp
实验任务5：
task5.cpp和Complex.hpp的源码，运行测试结果如下
#pragma once #include <iostream> using namespace std; template <typename T> class Complex { private: T real; T imag; public: Complex(const T& r = 0, const T& i = 0) : real { r }, imag { i } {} Complex operator+=(const Complex& c) { real += c.real; imag += c.imag; return *this; } friend Complex operator+(const Complex& c1, const Complex& c2) { return Complex<T>(c1.real + c2.real, c1.imag + c2.imag); } friend bool operator==(const Complex& c1, const Complex& c2) { return c1.real == c2.real && c1.imag == c2.imag; } friend ostream& operator<<(ostream& out, const Complex& c) { if (c.imag >= 0) out << c.real << "+" << c.imag << "i"; else out << c.real << "-" << -c.imag << "i"; return out; } friend istream& operator>>(istream& in, Complex& c) { in >> c.real >> c.imag; return in; } T get_real() const { return real; } T get_imag() const { return imag; } };
#include "Complex.hpp" #include <iostream> using std::cin; using std::cout; using std::endl; using std::boolalpha; void test1() { Complex<int> c1(2, -5), c2(c1); cout << "c1 = " << c1 << endl; cout << "c2 = " << c2 << endl; cout << "c1 + c2 = " << c1 + c2 << endl; c1 += c2; cout << "c1 = " << c1 << endl; cout << boolalpha << (c1 == c2) << endl; } void test2() { Complex<double> c1, c2; cout << "Enter c1 and c2: "; cin >> c1 >> c2; cout << "c1 = " << c1 << endl; cout << "c2 = " << c2 << endl; cout << "c1.real = " << c1.get_real() << endl; cout << "c1.imag = " << c1.get_imag() << endl; } int main() { cout << "自定义类模板Complex测试1: " << endl; test1(); cout << endl; cout << "自定义类模板Complex测试2: " << endl; test2(); }
实验任务6：
task6.cpp,data.h,date.cpp,accumulator.h,accout.h,account.cpp的源码，运行测试结果如下
#include"account.h" #include<iostream> using namespace std; int main() { Date date(2008, 11, 1); SavingsAccount sa1(date, "S3755217", 0.015); SavingsAccount sa2(date, "02342342", 0.015); CreditAccount ca(date, "C5392394", 10000, 0.0005, 50); Account* accounts[] = { &sa1,&sa2,&ca }; const int n = sizeof(accounts) / sizeof(Account*); cout << "(d)deposit (w)withdraw (s)show (c)change day (n)next month (e)exit" << endl; char cmd; do { date.show(); cout << "\tTotal:" << Account::getTotal() << "\tcommand>"; int index, day; double amount; string desc; cin >> cmd; switch (cmd) { case 'd': cin >> index >> amount; getline(cin, desc); accounts[index]->deposit(date, amount, desc); break; case 'w': cin >> index >> amount; getline(cin, desc); accounts[index]->withdraw(date, amount, desc); break; case 's': for (int i = 0; i < n; i++) { cout << "[" << i << "]"; accounts[i]->show(); cout << endl; } break; case 'c': cin >> day; if (day < date.getDay()) { cout << "You cannot specify a previous day"; } else if (day > date.getMaxDay()) cout << "Invalid day"; else date = Date(date.getYear(), date.getMonth(), day); break; case 'n': if (date.getMonth() == 12) date = Date(date.getYear() + 1, 1, 1); else date = Date(date.getYear(), date.getMonth() + 1, 1); for (int i = 0; i < n; i++) { accounts[i]->settle(date); } break; } } while (cmd != 'e'); return 0; }
#pragma once class Date { private: int year; int month; int day; int totalDays; public: Date(int year, int month, int day); int getYear()const { return year; } int getMonth()const { return month; } int getDay()const { return day; } int getMaxDay()const; bool isLeapYear()const { return year % 4 == 0 && year % 100 != 0 || year % 400 == 0; } void show()const; int operator-(const Date& date)const { return totalDays - date.totalDays; } };
#include"date.h" #include<iostream> #include<cstdlib> using namespace std; namespace { const int DAYS_BEFIRE_MONTH[] = { 0,31,59,90,120,151,181,212,243,273,304 ,334,365 }; } Date::Date(int year, int month, int day) :year(year), month(month), day(day) { if (day <= 0 || day > getMaxDay()) { cout << "Invalid date: "; show(); cout << endl; exit(1); } int years = year - 1; totalDays = years * 365 + years / 4 - years / 100 + years / 400 + DAYS_BEFIRE_MONTH[month - 1] + day; if (isLeapYear() && month > 2) totalDays++; } int Date::getMaxDay()const { if (isLeapYear() && month == 2) return 29; else return DAYS_BEFIRE_MONTH[month] - DAYS_BEFIRE_MONTH[month - 1]; } void Date::show()const { cout << getYear() << "-" << getMonth() << "-" << getDay(); }
#pragma once #include"date.h" class Accumulator { private: Date lastDate; double value; double sum; public: Accumulator(const Date& date, double value) :lastDate(date), value(value), sum { 0 } {} double getSum(const Date& date) const { return sum + value * (date - lastDate); } void change(const Date& date, double value) { sum = getSum(date); lastDate = date; this->value = value; } void reset(const Date& date, double value) { lastDate = date; this->value; sum = 0; } };
#pragma once #include"date.h" #include"accumulator.h" #include<string> using namespace std; class Account { private: string id; double balance; static double total; protected: Account(const Date& date, const string &id); void record(const Date& date, double amoount, const string& desc); void error(const string& msg) const; public: const string& getId() { return id; } double getBalance()const { return balance; } static double getTotal() { return total; } virtual void deposit(const Date& date, double amount, const string& desc) = 0; virtual void withdraw(const Date& date, double amount, const string& desc) = 0; virtual void settle(const Date& date) = 0; virtual void show()const; }; class SavingsAccount :public Account { private: Accumulator acc; double rate; public: SavingsAccount(const Date& date, const string& id, double rate); double getRate() const { return rate; } void deposit(const Date& date, double amount, const string& desc); void withdraw(const Date& date, double amount, const string& desc); void settle(const Date& date); }; class CreditAccount :public Account { private: Accumulator acc; double credit; double rate; double fee; double getDebt()const { double balance = getBalance(); return(balance < 0 ? balance : 0); } public: CreditAccount(const Date& date, const string& id, double credit, double rate, double fee); double getCredit()const { return credit; } double getRate()const { return rate; } double getFee() const { return fee; } double getAvailableCredit()const { if (getBalance() < 0)return credit + getBalance(); else return credit; } void deposit(const Date& date, double amount, const string& desc); void withdraw(const Date& date, double amount, const string& desc); void settle(const Date& date); void show()const; };
#include "account.h" #include <cmath> #include<iostream> using namespace std; double Account::total = 0; Account::Account(const Date& date, const string& id) :id(id), balance(0) { date.show(); cout << "\t#" << id << "created" << endl; } void Account::record(const Date& date, double amount, const string& desc) { amount = floor(amount * 100 + 0.5) / 100; balance += amount; total += amount; date.show(); cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl; } void Account::show()const { cout << id << "\tBalance:" << balance; } void Account::error(const string& msg)const { cout << "Error(#" << id << "):" << msg << endl; } SavingsAccount::SavingsAccount(const Date& date, const string& id, double rate) :Account(date, id), rate(rate), acc(date, 0) {} void SavingsAccount::deposit(const Date& date, double amount, const string& desc) { record(date, amount, desc); acc.change(date, getBalance()); } void SavingsAccount::withdraw(const Date& date, double amount, const string& desc) { if (amount > getBalance()) { error("not enough money"); } else { record(date, -amount, desc); acc.change(date, getBalance()); } } void SavingsAccount::settle(const Date& date) { double interest = acc.getSum(date) * rate / (date-Date(date.getYear() - 1, 1, 1)); if (interest != 0)record(date, interest, "interest"); acc.reset(date, getBalance()); } CreditAccount::CreditAccount(const Date& date, const string& id, double credit, double rate, double fee) :Account(date, id), credit(credit), rate(rate), fee(fee), acc(date, 0) {} void CreditAccount::deposit(const Date& date, double amount, const string& desc) { record(date, amount, desc); acc.change(date, getDebt()); } void CreditAccount::withdraw(const Date& date, double amount, const string& desc) { if (amount - getBalance() > credit) { error("not enouogh credit"); } else { record(date, -amount, desc); acc.change(date, getDebt()); } } void CreditAccount::settle(const Date& date) { double interest = acc.getSum(date) * rate; if (interest != 0) record(date, interest, "interest"); if (date.getMonth() == 1)record(date, -fee, "annual fee"); acc.reset(date, getDebt()); } void CreditAccount::show()const { Account::show(); cout << "\tAvailable credit:" << getAvailableCredit(); }
改进之后，效率得到了一定程度的提高。
