实验二 类和对象_基础编程1

实验任务一：

#pragma once#include <string>// 类T: 声明
class T {
// 对象属性、方法
public:T(int x = 0, int y = 0);   // 普通构造函数T(const T &t);  // 复制构造函数T(T &&t);       // 移动构造函数~T();           // 析构函数void adjust(int ratio);      // 按系数成倍调整数据void display() const;           // 以(m1, m2)形式显示T类对象信息private:int m1, m2;// 类属性、方法
public:static int get_cnt();          // 显示当前T类对象总数public:static const std::string doc;       // 类T的描述信息static const int max_cnt;           // 类T对象上限private:static int cnt;         // 当前T类对象数目// 类T友元函数声明friend void func();
};// 普通函数声明
void func();

// 类T: 实现
// 普通函数实现

#include "t.h"
#include <iostream>
#include <string>using std::cout;
using std::endl;
using std::string;// static成员数据类外初始化
const std::string T::doc{"a simple class sample"};
const int T::max_cnt = 999;
int T::cnt = 0;// 对象方法
T::T(int x, int y): m1{x}, m2{y} { ++cnt; cout << "T constructor called.\n";
} T::T(const T &t): m1{t.m1}, m2{t.m2} {++cnt;cout << "T copy constructor called.\n";
}T::T(T &&t): m1{t.m1}, m2{t.m2} {++cnt;cout << "T move constructor called.\n";
}    T::~T() {--cnt;cout << "T destructor called.\n";
}           void T::adjust(int ratio) {m1 *= ratio;m2 *= ratio;
}    void T::display() const {cout << "(" << m1 << ", " << m2 << ")" ;
}     // 类方法
int T::get_cnt() {return cnt;
}// 友元
void func() {T t5(42);t5.m2 = 2049;cout << "t5 = "; t5.display(); cout << endl;
}

#include "t.h"
#include <iostream>using std::cout;
using std::endl;void test();int main() {test();cout << "\nmain: \n";cout << "T objects'current count: " << T::get_cnt() << endl;
}void test() {cout << "test class T: \n";cout << "T info: " << T::doc << endl;cout << "T objects'max count: " << T::max_cnt << endl;cout << "T objects'current count: " << T::get_cnt() << endl << endl;T t1;cout << "t1 = "; t1.display(); cout << endl;T t2(3, 4);cout << "t2 = "; t2.display(); cout << endl;T t3(t2);t3.adjust(2);cout << "t3 = "; t3.display(); cout << endl;T t4(std::move(t2));cout << "t3 = "; t4.display(); cout << endl;cout << "T objects'current count: " << T::get_cnt() << endl;func();
}

问题一：

不能，编译器找不到标识符，因为友元函数只声明在类中，声明被封装到类中，对外不可见，如果不在外声明则找不到

问题二：

普通构造函数：用来创建对象； 在创建对象时调用

复制构造函数：用来给对象赋值 ；  1、用一个对象初始化另一个对象时调用 2、在调用函数使用值传递时，将实参赋值给形参 3、在返回对象的函数调用中，返回一个对象时创建的临时对象时调用

移动构造函数：避免拷贝对象，而是改变资源指向，提高效率  ； 在显示调用移动构造函数时调用

 析构函数：用来对象被删除前的清理工作，调用后，对象将不存在； 在对象生存期快要结束时调用

问题三：不可以

 

实验任务二：

#pragma once
#include<string>
using namespace std;
class Complex {
private:double real;double imag;public:static string doc;Complex(double x = 0, double y = 0);Complex(const Complex& c);double get_real() const;double get_imag() const ;void add(const Complex &c);friend Complex add(const Complex &c1,const  Complex &c2);friend    bool is_equal(const Complex& c1, const  Complex& c2);friend bool is_not_equal(const Complex& c1, const  Complex& c2);friend void output(const Complex &c);friend double abs(const Complex &c);
};
//普通函数声明
Complex add(const Complex& c1, const  Complex& c2);
bool is_equal(const Complex& c1, const  Complex& c2);
bool is_not_equal(const Complex& c1, const  Complex& c2);
void output(const Complex& c);
double abs(const Complex& c);

#include "C:/Users/29114/source/repos/MAJORCPP/Complex.h"
#include<iostream>
#include<math.h>
using namespace std;string Complex ::doc = "a simplified complex class";Complex ::Complex(double x, double y ):real(x),imag(y){}Complex::Complex(const Complex& c) { real = c.real;imag = c.imag;}double Complex::get_real() const {return real;}double Complex::get_imag() const {return imag;}void Complex::add(const Complex& c) {real = c.real + real;imag += c.imag;}Complex add(const Complex& c1, const  Complex& c2) {return Complex(c1.real + c2.real, c1.imag + c2.imag);}
bool is_equal(const Complex& c1, const  Complex& c2) {if (c1.real == c2.real &&c2.imag == c1.imag)return true;elsereturn false;
}
bool is_not_equal(const Complex& c1, const  Complex& c2) {if (is_equal(c1,c2))return false;elsereturn true;
}void output(const Complex& c) {if(c.imag>=0)cout << c.real << " + " << c.imag << "i";elsecout << c.real << c.imag << "i";
}double abs(const Complex& c) {return sqrt(c.real * c.real + c.imag * c.imag);
}

#include <iostream>
#include "C:/Users/29114/source/repos/MAJORCPP/Complex.h"using std::cout;
using std::endl;
using std::boolalpha;void test() {cout << "类成员测试: " << endl;cout << Complex::doc << endl;cout << endl;cout << "Complex对象测试: " << endl;Complex c1;Complex c2(3, -4);const Complex c3(3.5);Complex c4(c3);cout << "c1 = "; output(c1); cout << endl;cout << "c2 = "; output(c2); cout << endl;cout << "c3 = "; output(c3); cout << endl;cout << "c4 = "; output(c4); cout << endl;cout << "c4.real = " << c4.get_real() << ", c4.imag = " << c4.get_imag() << endl;cout << endl;cout << "复数运算测试: " << endl;cout << "abs(c2) = " << abs(c2) << endl;c1.add(c2);cout << "c1 += c2, c1 = "; output(c1); cout << endl;cout << boolalpha;cout << "c1 == c2 : " << is_equal(c1, c2) << endl;cout << "c1 != c3 : " << is_not_equal(c1, c3) << endl;c4 = add(c2, c3);cout << "c4 = c2 + c3, c4 = "; output(c4); cout << endl;
}int main() {test();
}

实验任务三：

#include <iostream>
#include <complex>using std::cout;
using std::endl;
using std::boolalpha;
using std::complex;void test() {cout << "标准库模板类comple测试: " << endl;complex<double> c1;complex<double> c2(3, -4);const complex<double> c3(3.5);complex<double> c4(c3);cout << "c1 = " << c1 << endl;cout << "c2 = " << c2 << endl;cout << "c3 = " << c3 << endl;cout << "c4 = " << c4 << endl;cout << "c4.real = " << c4.real() << ", c4.imag = " << c4.imag() << endl;cout << endl;cout << "复数运算测试: " << endl;cout << "abs(c2) = " << abs(c2) << endl;c1 += c2;cout << "c1 += c2, c1 = " << c1 << endl;cout << boolalpha;cout << "c1 == c2 : " << (c1 == c2) << endl;cout << "c1 != c3 : " << (c1 != c3) << endl;c4 = c2 + c3;cout << "c4 = c2 + c3, c4 = " << c4 << endl;
}int main() {test();
}

使用了相应的构造函数，使用了加、取模等操作

实验任务4：

#pragma once
#include<iostream>
using namespace std;
class Fraction {
public:const static  string doc;
private:int up;int down;
public://先声明，在.cpp中实现Fraction(int n);Fraction(int a, int b);Fraction(const Fraction& p);int get_up();int get_down();Fraction negative();//返回求负对象
friend void output(Fraction a);friend Fraction add(Fraction a, Fraction b);friend Fraction sub(Fraction a, Fraction b);friend Fraction mul(Fraction a, Fraction b);friend Fraction div(Fraction a, Fraction b);};
//普通函数声明
void output(Fraction a);
Fraction add(Fraction a, Fraction b);
Fraction sub(Fraction a, Fraction b);
Fraction mul(Fraction a, Fraction b);
Fraction div(Fraction a, Fraction b);
int gcd(int a, int b);

#include"Fraction.h"
#include<iostream>
#include<cstdlib>using namespace std;
/*
Fraction(int n):up=n,down=1{}Fraction(int a,int b):up=a,down=b{}Fraction(const Fraction &p);int get_up(Fraction a);int get_down(Fraction a);Fraction negative();//返回求负对象friend void output(Fraction a);friend Fraction add(Fraction a,Fraction b);friend Fraction sub(Fraction a,Fraction b);friend Fraction mul(Fraction a,Fraction b);friend Fraction div(Fraction a,Fraction b);
*/
const string Fraction::doc = "Fraction类 v 0.01版.目前仅支持分数对象的构造、输出、加/减/乘/除运算.";
Fraction::Fraction(int n) :up(n), down(1){}
Fraction::Fraction(int x,int y) :up(x), down(y) {}
Fraction::Fraction(const Fraction& p) :up(p.up), down(p.down){}
int Fraction::get_up() {return up/ gcd(up, down);
}
int Fraction::get_down() {return down / gcd(up, down);
}
Fraction Fraction::negative() {Fraction a(-1*up,down);return a;
}
void output(Fraction a) {int b = gcd(a.up, a.down);if ((a.up < 0 && a.down>0) || (a.up > 0 && a.down < 0))cout << "-" << abs(a.up / b) << "/" << abs(a.down / b);else if (a.down == 1)cout << a.up;else if (a.down == 0)cout << "分子不能为0";else if (a.up == 0)cout << "0";elsecout << a.up / b << "/" << a.down / b;}
Fraction add(Fraction a, Fraction b) {int down1 = abs(a.down * b.down) / gcd(a.down, b.down);int up1 = down1 / a.down * a.up+ down1 / b.down * b.up;Fraction c(up1, down1);return c;
}
Fraction sub(Fraction a, Fraction b) {int down = abs(a.down * b.down) / gcd(a.down, b.down);int up1 = down / a.down * a.up;int up2 = down / b.down * b.up;Fraction c(up1 - up2, down);return  c;
}
Fraction mul(Fraction a, Fraction b) {Fraction c(a.up * b.up, a.down * b.down);return c;
}
Fraction div(Fraction a, Fraction b) {Fraction c(a.up * b.down, a.down * b.up);return c;
}
int gcd(int a, int b) {while (b != 0) {int temp = b;b = a % b;a = temp;}return a;
}

#include <iostream>
#include "C:/Users/29114/source/repos/MAJORCPP/Fraction.h"using std::cout;
using std::endl;void test1() {cout << "Fraction类测试: " << endl;cout << Fraction::doc << endl << endl;Fraction f1(5);Fraction f2(3, -4), f3(-18, 12);Fraction f4(f3);cout << "f1 = "; output(f1); cout << endl;cout << "f2 = "; output(f2); cout << endl;cout << "f3 = "; output(f3); cout << endl;cout << "f4 = "; output(f4); cout << endl;Fraction f5(f4.negative());cout << "f5 = "; output(f5); cout << endl;cout << "f5.get_up() = " << f5.get_up() << ", f5.get_down() = " << f5.get_down() << endl;cout << "f1 + f2 = "; output(add(f1, f2)); cout << endl;cout << "f1 - f2 = "; output(sub(f1, f2)); cout << endl;cout << "f1 * f2 = "; output(mul(f1, f2)); cout << endl;cout << "f1 / f2 = "; output(div(f1, f2)); cout << endl;cout << "f4 + f5 = "; output(add(f4, f5)); cout << endl;
}void test2() {Fraction f6(42, 55), f7(0, 3);cout << "f6 = "; output(f6); cout << endl;cout << "f7 = "; output(f7); cout << endl;cout << "f6 / f7 = "; output(div(f6, f7)); cout << endl;
}int main() {cout << "测试1: Fraction类基础功能测试\n";test1();cout << "\n测试2: 分母为0测试: \n";test2();
}

实验任务5

 

#ifndef ACCOUNT_H
#define ACCOUNT_H
#include<iostream>
class SavingAccount{private:int id;double balance;double rate;int lastDate;double accumulation;static double total;void record(int date,double amount);double accumulate(int date)const{return accumulation+balance*(date-lastDate);}public:SavingAccount(int date,int id,double rate);int getId()const{return id;}double getBalance()const{return balance;}double getRate()const{return rate;}static double getTotal(){return total;}void deposit(int date,double amount);//存入现金 void withdraw(int date,double amount);//取出现金//结算利息，每年1月1日调用一次下函数void settle(int date);void show()const; 
};
#endif

#include"account.h"
#include<iostream>
#include<cmath>
using namespace std;
double SavingAccount::total=0;
SavingAccount::SavingAccount(int date,int id,double rate):id{id},balance(0),rate(rate),lastDate(date),accumulation(0){cout<<date<<"\t#"<<id<<"is created"<<endl;    
}
void SavingAccount::record(int date,double amount){accumulation=accumulate(date);lastDate=date;amount=floor(amount*100+0.5)/100;balance+=amount;total+=amount;cout<<date<<"\t#"<<id<<"\t"<<amount<<"\t"<<balance<<endl;
}
void SavingAccount::deposit(int date,double amount)
{record(date,amount);
}
void SavingAccount::withdraw(int date,double amount)
{if(amount>getBalance())cout<<"Error:not enough money"<<endl;elserecord(date,-amount);
}
void SavingAccount::settle(int date)
{double interest=accumulate(date)*rate/365;if(interest!=0)record(date,interest);accumulation=0;
}
void SavingAccount::show()const
{cout<<"#"<<id<<"\tBalance:"<<balance;
}

#include"account.h"
#include<iostream>
using namespace std;
int main()
{SavingAccount sa0(1,21325302,0.015);SavingAccount sa1(1,58320212,0.015);sa0.deposit(5,5000);sa1.deposit(25,10000);sa0.deposit(45,5500);sa1.withdraw(60,4000);sa0.settle(90);sa1.settle(90);sa0.show();cout<<endl;sa1.show();cout<<endl;cout<<"Total:"<<SavingAccount::getTotal()<<endl;return 0;
}