实验三
实验任务1
button.hpp代码
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#pragma once
#include <iostream>
#include <string>
using std::string;
using std::cout;
// 按钮类
class Button {
public:
Button(const string &text);
string get_label() const;
void click();
private:
string label;
};
Button::Button(const string &text): label{text} {}
inline string Button::get_label() const {
return label;
}
void Button::click() {
cout << "Button '" << label << "' clicked\n";
}
window.hpp代码
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#pragma once
#include "button.hpp"
#include <vector>
#include <iostream>
using std::vector;
using std::cout;
using std::endl;
// 窗口类
class Window{
public:
Window(const string &win_title);
void display() const;
void close();
void add_button(const string &label);
private:
string title;
vector<Button> buttons;
};
Window::Window(const string &win_title): title{win_title} {
buttons.push_back(Button("close"));
}
inline void Window::display() const {
string s(40, '*');
cout << s << endl;
cout << "window title: " << title << endl;
cout << "It has " << buttons.size() << " buttons: " << endl;
for(const auto &i: buttons)
cout << i.get_label() << " button" << endl;
cout << s << endl;
}
void Window::close() {
cout << "close window '" << title << "'" << endl;
buttons.at(0).click();
}
void Window::add_button(const string &label) {
buttons.push_back(Button(label));
}
task1.cpp代码
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#include "window.hpp"
#include <iostream>
using std::cout;
using std::cin;
void test() {
Window w1("new window");
w1.add_button("maximize");
w1.display();
w1.close();
}
int main() {
cout << "用组合类模拟简单GUI:\n";
test();
}
运行结果：
实验任务2
task2.cpp代码
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#include <iostream>
#include <vector>
using namespace std;
void output1(const vector<int> &v) {
for(auto &i: v)
cout << i << ", ";
cout << "\b\b \n";
}
void output2(const vector<vector<int>> v) {
for(auto &i: v) {
for(auto &j: i)
cout << j << ", ";
cout << "\b\b \n";
}
}
void test1() {
vector<int> v1(5, 42);
const vector<int> v2(v1);
v1.at(0) = -999;
cout << "v1: "; output1(v1);
cout << "v2: "; output1(v2);
cout << "v1.at(0) = " << v1.at(0) << endl;
cout << "v2.at(0) = " << v2.at(0) << endl;
}
void test2() {
vector<vector<int>> v1{{1, 2, 3}, {4, 5, 6, 7}};
const vector<vector<int>> v2(v1);
v1.at(0).push_back(-999);
cout << "v1: \n"; output2(v1);
cout << "v2: \n"; output2(v2);
vector<int> t1 = v1.at(0);
cout << t1.at(t1.size()-1) << endl;
const vector<int> t2 = v2.at(0);
cout << t2.at(t2.size()-1) << endl;
}
int main() {
cout << "测试1:\n";
test1();
cout << "\n测试2:\n";
test2();
}
运行结果：
问题1：
line21定义了一个有五个元素，初值为42的vector对象v1
line22复制v1构造了v2
line24给v1的第一个元素重新赋值-999
问题2：
line32定义了以vector为成员类型的vector对象v1
line33复制v1构造了const修饰的v2
line35给v1的第一个成员追加了一个-999
问题3：
line39定义了vector类型的t1，用v1的第一个成员给t1赋初值
line40输出了t1的最后一个元素
line42定义了const修饰的vector类型的t2，用v2的第一个成员给t2赋初值
line43输出了t1的最后一个元素
问题4：
1.浅复制
2是
实验任务3
vectorInt.hpp代码
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#pragma once
#include <iostream>
#include <cassert>
using std::cout;
using std::endl;
// 动态int数组对象类
class vectorInt{
public:
vectorInt(int n);
vectorInt(int n, int value);
vectorInt(const vectorInt &vi);
~vectorInt();
int& at(int index);
const int& at(int index) const;
vectorInt& assign(const vectorInt &v);
int get_size() const;
private:
int size;
int *ptr;
};
vectorInt::vectorInt(int n): size{n}, ptr{new int[size]} {
}
vectorInt::vectorInt(int n, int value): size{n}, ptr{new int[size]} {
for(auto i = 0; i < size; ++i)
ptr[i] = value;
}
vectorInt::vectorInt(const vectorInt &vi): size{vi.size}, ptr{new int[size]}
{
for(auto i = 0; i < size; ++i)
ptr[i] = vi.ptr[i];
}
vectorInt::~vectorInt() {
delete [] ptr;
}
const int& vectorInt::at(int index) const {
assert(index >= 0 && index < size);
return ptr[index];
}
int& vectorInt::at(int index) {
assert(index >= 0 && index < size);
return ptr[index];
}
vectorInt& vectorInt::assign(const vectorInt &v) {
delete[] ptr;
// 释放对象中ptr原来指向的资源
size = v.size;
ptr = new int[size];
for(int i = 0; i < size; ++i)
ptr[i] = v.ptr[i];
return *this;
}
int vectorInt::get_size() const {
return size;
}
task3.cpp代码
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#include "vectorInt.hpp"
#include <iostream>
using std::cin;
using std::cout;
void output(const vectorInt &vi) {
for(auto i = 0; i < vi.get_size(); ++i)
cout << vi.at(i) << ", ";
cout << "\b\b \n";
}
void test1() {
int n;
cout << "Enter n: ";
cin >> n;
vectorInt x1(n);
for(auto i = 0; i < n; ++i)
x1.at(i) = i*i;
cout << "x1: "; output(x1);
vectorInt x2(n, 42);
vectorInt x3(x2);
x2.at(0) = -999;
cout << "x2: "; output(x2);
cout << "x3: "; output(x3);
}
void test2() {
const vectorInt x(5, 42);
vectorInt y(10, 0);
cout << "y: "; output(y);
y.assign(x);
cout << "y: "; output(y);
cout << "x.at(0) = " << x.at(0) << endl;
cout << "y.at(0) = " << y.at(0) << endl;
}
int main() {
cout << "测试1: \n";
test1();
cout << "\n测试2: \n";
test2();
}
运行结果：
问题1：
深复制
问题2：
能正常运行。存在安全隐患，返回的值可能被改变，不符合该接口的预期。
问题3：
可以；这里将返回值的引用类型修改只会导致复制类型的变化，不会明显影响程序运行。
实验任务4
matrix.hpp代码
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#include <iostream>
#include <cassert>
using std::cin;
using std::cout;
using std::endl;
const int N = 1000;
// 类Matrix的声明
class Matrix {
public:
Matrix(int n, int m);// 构造函数，构造一个n*m的矩阵, 初始值为value
Matrix(int n);// 构造函数，构造一个n*n的矩阵, 初始值为value
Matrix(const Matrix &x);// 构造函数，构造一个n*n的矩阵, 初始值为value
~Matrix();
void set(const double *pvalue);// 用pvalue指向的连续内存块数据按行为矩阵赋值
void clear();// 把矩阵对象的值置0
const double& at(int i, int j) const;// 返回矩阵对象索引(i,j)的元素const引用
double& at(int i, int j);// 返回矩阵对象索引(i,j)的元素引用
int get_lines() const;// 返回矩阵对象行数
int get_cols() const;// 返回矩阵对象列数
void display() const;// 按行显示矩阵对象元素值
private:
int lines; // 矩阵对象内元素行数
int cols; // 矩阵对象内元素列数
double *ptr;
};
Matrix::Matrix(int n,int m):lines{n},cols{m},ptr{new double[n*m]}{
}
Matrix::Matrix(int n):lines{n},cols{n},ptr{new double[n*n]}{
}
Matrix::Matrix(const Matrix &x){
lines=x.lines;
cols=x.cols;
ptr=new double[lines*cols];
for(int i=0;i<x.lines*x.cols;i++){
ptr[i]=x.ptr[i];
}
}
Matrix::~Matrix(){
delete [] ptr;
}
void Matrix::set(const double *pvalue){
for(int i=0;i<lines*cols;i++){
ptr[i]=pvalue[i];
}
}
void Matrix::clear(){
for(int i=0;i<lines*cols;i++){
ptr[i]=0;
}
}
const double& Matrix::at(int i,int j) const{
return ptr[i*cols+j];
}
double& Matrix::at(int i,int j){
return ptr[i*cols+j];
}
int Matrix::get_lines() const{
return lines;
}
int Matrix::get_cols() const{
return cols;
}
void Matrix::display() const{
int k=0;
for(int i=0;i<lines;i++){
for(int j=0;j<cols;j++){
if(j==cols-1){
cout<<ptr[k];
}
else{
cout<<ptr[k]<<",";
}
k++;
}
cout<<endl;
}
}
task4.cpp代码
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#include "matrix.hpp"
#include <iostream>
#include <cassert>
using std::cin;
using std::cout;
using std::endl;
void output(const Matrix &m, int index) {
assert(index >= 0 && index < m.get_lines());
for(auto j = 0; j < m.get_cols(); ++j)
cout << m.at(index, j) << ", ";
cout << "\b\b \n";
}
void test1() {
double x[1000] = {1, 2, 3, 4, 5, 6, 7, 8, 9};
int n, m;
cout << "Enter n and m: ";
cin >> n >> m;
Matrix m1(n, m);
m1.set(x);
Matrix m2(m, n);
m2.set(x);
Matrix m3(2);
m3.set(x);
cout << "矩阵对象m1: \n"; m1.display(); cout << endl;
cout << "矩阵对象m2: \n"; m2.display(); cout << endl;
cout << "矩阵对象m3: \n"; m3.display(); cout << endl;
}
void test2() {
Matrix m1(2, 3);
m1.clear();
const Matrix m2(m1);
m1.at(0, 0) = -999;
cout << "m1.at(0, 0) = " << m1.at(0, 0) << endl;
cout << "m2.at(0, 0) = " << m2.at(0, 0) << endl;
cout << "矩阵对象m1第0行: "; output(m1, 0);
cout << "矩阵对象m2第0行: "; output(m2, 0);
}
int main(){
cout << "测试1: \n";
test1();
cout << "测试2: \n";
test2();
}
运行结果：
实验任务5
user.hpp代码
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#include<iostream>
#include<vector>
#include<string>
using std::cin;
using std::cout;
using std::endl;
using std::vector;
using std::string;
class User{
public:
User(string n,string p="123456",string e="NULL");
void set_email();
void change_password();
void display() const;
private:
string name;
string password;
string email;
};
User::User(string n,string p,string e){
name=n;
password=p;
email=e;
}
void User::set_email(){
string em;
cout<<"Enter email address:";
while(cin>>em){
int count=0;
for(int i=0;i<em.size();i++){
if(em[i]=='@'){
count++;
}
}
if(count){
email=em;
cout<<"email is set successfully..."<<endl;
break;
}
else{
cout<<"illegal email.Please re-enter email:";
}
}
}
void User::change_password(){
string oe,ne;
int count=0;
cout<<"Enter old password:";
cin>>oe;
for(int i=0;i<3;i++){
if(oe==password){
cout<<"Enter new password:";
cin>>ne;
email=ne;
cout<<"new password is set succesfully"<<endl;
break;
}
else{
count++;
if(count==3){
cout<<"password input error.Please try after a while."<<endl;
break;
}
cout<<"password input error.Please re-enter again:";
cin>>oe;
}
}
}
void User::display() const{
cout<<"name:"<<name<<endl;
int i=password.size();
for(int j=0;j<i;j++){
cout<<"*";
}
cout<<endl;
cout<<"email:"<<email<<endl;
}
task5.cpp代码
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#include"user.hpp"
#include<iostream>
#include<vector>
#include<string>
using std::cin;
using std::cout;
using std::endl;
using std::vector;
using std::string;
void test() {
vector<User> user_lst;
User u1("Alice", "2024113", "Alice@hotmail.com");
user_lst.push_back(u1);
cout << endl;
User u2("Bob");
u2.set_email();
u2.change_password();
user_lst.push_back(u2);
cout << endl;
User u3("Hellen");
u3.set_email();
u3.change_password();
user_lst.push_back(u3);
cout << endl;
cout << "There are " << user_lst.size() << " users. they are: " << endl;
for(auto &i: user_lst) {
i.display();
cout << endl;
}
}
int main() {
test();
}
运行结果：
实验任务6
date.h代码
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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 distance(const Date &date)const {
return totalDays - date.totalDays;
}
};
date.cpp代码
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#include"date.h"
#include<iostream>
#include<cstdlib>
using namespace std;
namespace {
const int DAYS_BEFORE_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 = year * 365 + years / 4 - years / 100 + years / 400 + DAYS_BEFORE_MONTH[month - 1] + day;
if (isLeapYear() && month > 2) totalDays++;
}
int Date::getMaxDay()const {
if (isLeapYear() && month == 2)
return 29;
else
return DAYS_BEFORE_MONTH[month] - DAYS_BEFORE_MONTH[month - 1];
}
void Date::show() const {
cout << getYear() <<"-"<< getMonth() <<"-"<< getDay();
}
account.h代码
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#include"date.h"
#include<string>
class SavingsAccount{
private:
std::string id;
double balance;
double rate;
Date lastDate;
double accumulation;
static double total;
void record(const Date &date, double amount,const std::string &desc);
void error(const std::string &msg)const;
double accumulate(const Date &date) const{
return accumulation + balance*date.distance(lastDate);
}
public:
SavingsAccount(const Date &date, const std::string &id, double rate);
const std::string &getId() const { return id; }
double getBalance() const { return balance; }
double getRate() const { return rate; }
static double getTotal() { return total; }
void deposit(const Date &date, double amount, const std::string &desc);
void withdraw(const Date &date, double amount,const std::string &desc);
void settle(const Date &date);
void show() const;
};
account.cpp代码
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#include "account.h"
#include<cmath>
#include<iostream>
using namespace std;
double SavingsAccount::total = 0;
SavingsAccount::SavingsAccount(const Date &date, const string &id, double rate): id(id), balance(0), rate(rate), lastDate(date), accumulation(0){
date.show();
cout << "\t#" << id << " created" << endl;
}
void SavingsAccount::record(const Date &date, double amount, const string &desc){
accumulation = accumulate(date);
lastDate = date;
amount = floor(amount * 100 + 0.5) / 100; //保留小数点后两位
balance += amount;
total += amount;
date.show();
cout <<"\t#" << id << "\t" << amount << "\t" << balance << "\t" <<desc<< endl;
}
void SavingsAccount::error(const string &msg)const{
cout<<"Error(#"<<id<<"):"<<msg<<endl;
}
void SavingsAccount::deposit(const Date &date, double amount, const string &desc){
record(date, amount,desc);
}
void SavingsAccount::withdraw(const Date &date, double amount, const string &desc){
if (amount > getBalance())
error("not enough money");
else
record(date, -amount,desc);
}
void SavingsAccount::settle(const Date &date){
double interest = accumulate(date)*rate / date.distance(Date(date.getYear()-1, 1, 1)); //计算年息
if (interest != 0)
record(date, interest,"interest");
accumulation = 0;
}
void SavingsAccount::show() const{
cout << id << "\tBalance:" << balance;
}
6_25代码
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#include"account.h"
#include<iostream>
using namespace std;
int main(){
Date date(2008, 11, 1);
SavingsAccount accounts[] = {
SavingsAccount(date, "03755217", 0.015),
SavingsAccount(date, "02342342", 0.015)
};
const int n = sizeof(accounts) / sizeof(SavingsAccount);
accounts[0].deposit(Date(2008, 11, 5), 5000, "salary");
accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
accounts[0].deposit(Date(2008, 12, 5), 5500, "salary");
accounts[1].withdraw(Date(2008, 12, 20), 4000, "buy a laptop");
cout << endl;
for (int i = 0;i < n;i++) {
accounts[i].settle(Date(2009, 1, 1));
accounts[i].show();
cout << endl;
}
cout << "Total: " << SavingsAccount::getTotal() << endl;
return 0;
}
运行结果：
