实验2

task1

#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1：

重新编译，不能正确运行。

 全局函数作友元需类外声明定义，去掉line36后,func作为私有成员报错was not declared in this scope

问题2：

普通构造：t1、t2.初始化实例化对象，t1 默认00，t2以传值34初始化。

复制构造：t3。使用同类型的对象t2去初始化实例对象。

移动构造：t4。将对象t2控制的内存空间转移给构造出的对象t4。

构造函数在创建对象时调用进行初始化，析构函数在对象销毁进行清理工作。

问题3：

不能正确编译运行。

task2

#ifndef COMPLEX_H
#define COMPLEX_H
#include<string>
#include<iostream>
#include<cmath>
class Complex{
    public:
        static const std::string doc;
        
        Complex();
        
        Complex(double real);
        
        Complex(double real,double imag);
        
        Complex(const Complex& other);
        
        double get_real()const;
        
        double get_imag()const;
        
        void add(const Complex& other);
        
        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);
        
        private:
        double real;
        double imag; 
};
#endif

#include"Complex.h"

const std::string Complex::doc="a simplified Complex class";

Complex::Complex():real(0.0),imag(0.0){}

Complex::Complex(double real):real(real),imag(0.0){}

Complex::Complex(double real,double imag):real(real),imag(imag){}

Complex::Complex(const Complex& other):real(other.real),imag(other.imag){}

double Complex::get_real()const{
   return real;
}

double Complex::get_imag()const{
   return imag;
}

void Complex::add(const Complex& other){
    real+=other.real;
    imag+=other.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){
    return (c1.real==c2.real&&c1.imag==c2.imag);
}

bool is_not_equal(const Complex& c1,const Complex& c2){
    return !is_equal(c1,c2);
}

void output(const Complex& c){
    if(c.imag>=0){
        std::cout<<c.real<<"+"<<c.imag<<"i";
    }
    else{
        std::cout<<c.real<<"-"<<-c.imag<<"i";
    }
}

double abs(const Complex& c){
    return std::sqrt(c.real*c.real+c.imag*c.imag);
}

#include "Complex.h"
#include <iostream>

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();
}

task3

#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();
}

 task4

#ifndef FRACTION_H
#define FRACTION_H
#include<iostream>
#include<string>
class Fraction{
    public:
        static const std::string doc;
        Fraction(int up,int down=1);
        Fraction(const Fraction& other);
        int get_up() const;
        int get_down() const;
        Fraction negative() const;
        friend void output(const Fraction& f);
        friend Fraction add(const Fraction& f1,const Fraction& f2);
        friend Fraction sub(const Fraction& f1,const Fraction& f2);
        friend Fraction mul(const Fraction& f1,const Fraction& f2);
        friend Fraction div(const Fraction& f1,const Fraction& f2);
    private:
        int up;//分子 
        int down;//分母 
        void simplify();
};
#endif

#include"Fraction.h"
const std::string Fraction::doc="Fraction类 v 0.01版.\n目前仅支持分数对象的构造、输出、加/减/乘/除运算.";
Fraction::Fraction(int up,int down):up(up),down(down){
          if(down==0){
                std::cout<<"分母不能为0";
            }
            simplify();
            }
Fraction::Fraction(const Fraction& other):up(other.up),down(other.down){}
int Fraction::get_up() const{
        return up;}
int Fraction::get_down() const{
        return down;}
Fraction Fraction::negative() const{
            return Fraction(-up,down);
    }
    void Fraction::simplify() {
    int i,m,n;
            m=up;
            n=down;
            for(i=m%n;i!=0;i=m%n)
            m=n,n=i;
            up/=n;
            down/=n;
            if(down<0){
                up*=-1;
                down*=-1;
            }
}
void output(const Fraction& f){
            if(f.up==0)std::cout<<"0";
            else if(f.down==1)std::cout<<f.up;
            else
            std::cout<<f.up<<"/"<<f.down;
        }
    Fraction add(const Fraction& f1,const Fraction& f2){
        int new_up=f1.up*f2.down+f2.up*f1.down;
        int new_down=f1.down*f2.down;
        return Fraction(new_up,new_down);
    }
    Fraction sub(const Fraction& f1,const Fraction& f2){
        int new_up=f1.up*f2.down-f2.up*f1.down;
        int new_down=f1.down*f2.down;
        return Fraction(new_up,new_down);
    }
     Fraction mul(const Fraction& f1,const Fraction& f2){
        int new_up=f1.up*f2.up;
        int new_down=f1.down*f2.down;
        return Fraction(new_up,new_down);
    }
     Fraction div(const Fraction& f1,const Fraction& f2){
        int new_up=f1.up*f2.down;
        int new_down=f2.up*f1.down;
        return Fraction(new_up,new_down);
    } 

#include "Fraction.h"
#include <iostream>

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();
}

 task5

#ifndef __ACCOUNT_H__
#define __ACCOUNT_H__
class SavingsAccount{
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:
SavingsAccount(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);        
void withdraw(int date, double amount);
void settle(int date);    
void show() const;
};
#endif 

#include "account.h" 
#include <cmath> 
#include <iostream> 
using namespace std;

double SavingsAccount::total=0;
SavingsAccount::SavingsAccount(int date, int id, double rate)
:id(id),balance(0),rate(rate),lastDate(date),accumulation(0){ 
cout<<date<<"\t# "<< id<<" is created"<<endl;
}
void SavingsAccount::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 SavingsAccount::deposit(int date, double amount){
record(date,amount);
}
void SavingsAccount::withdraw(int date, double amount) {
if (amount>getBalance())
cout<<"Error: not enough money"<<endl; 
else
record(date,-amount);
}
void SavingsAccount::settle(int date) {
double interest=accumulate(date) * rate/365;
if (interest !=0)
record(date,interest); 
accumulation=0;
}
void SavingsAccount::show() const {
cout<< "#"<<id<<"\tBalance:"<<balance;
}

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

静态成员 total 的初始化可以在头文件中直接声明和初始化。

record中，金额的四舍五入处理可以放在一个单独的辅助函数中，提高代码的可维护性。