实验2 类和对象-基础编程1

实验任务1：

t.h, t.cpp, task1.cpp源码，运行测试结果如下

//t.h内容为类T的申明，友元函数的声明

#pragma once

#include <string>

class T {

    public:
        T(int x=0, int y=0);
        T(const T &t);
        T(T &&t);
        ~T();

        void adjust(int ratio);
        void display() const;

    private:
        int m1,m2;

    public:
        static int get_cnt();

    public:
        static const std::string doc;
        static const int max_cnt;

    private:
        static int cnt;

        friend void func();
};

void func();

//类T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 constructoor 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：

默认构造函数：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：可以

 

实验任务2：

Complex.h, Complex.cpp, task2.cpp源码,运行测试结果如下

#pragma once

#include<string>

//类Complex声明
class Complex{

public:
    Complex(double x=0,double y=0);
    Complex(const Complex&c);
    ~Complex();

    void add(const Complex&c);

public:

   static const std::string doc;
   int get_real();
   int get_imag();

private:
    double real;
    double imag;

    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);
};

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

using namespace std;

const 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} {}
Complex::~Complex() {}

void Complex::add(const Complex&c){
    real +=c.real;
    imag +=c.imag;
}

int Complex::get_real(){
    return real;
}
int Complex::get_imag(){
    return 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&&c1.imag==c2.imag)return true;
    else return false;

}
bool is_not_equal(const Complex&c1,const Complex&c2){
    if(c1.real==c2.real&&c1.imag==c2.imag)return false;
    else return true;

}
void output(const Complex&c){
    if(c.imag>=0){
        cout<<c.real<<"+"<<c.imag<<"i";
    }
    else{
        cout<<c.real<<"-"<<c.imag*(-1)<<"i";
    }
}
double abs(const Complex&c){
    return sqrt(c.real*c.real+c.imag*c.imag);
}

// 待补足头文件
#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();
}

 

实验任务3：

task3.cpp源代码，运行测试结果如下

#include <iostream>
#include <complex>

using namespace std;

void test (){
    cout <<"标准库模版类complex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();
}

 

实验任务4：

Fraction.h, Fraction.cpp, task4.cpp源码，运行测试结果如下

#pragma once

#include<string>
using namespace std;
class  Fraction{

public:
    Fraction(int x=0,int y=1);
    Fraction(const Fraction &f);
    ~Fraction();

    int get_up();
    int get_down() ;
    Fraction negative() const;
private:
    int m1;
    int m2;
    void simp();
public:
    static const string doc;
private:
    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);


};

void output(const Fraction &f);
Fraction add(const Fraction &f1,const Fraction &f2);
Fraction sub(const Fraction &f1,const Fraction &f2);
Fraction mul(const Fraction &f1,const Fraction &f2);
Fraction div(const Fraction &f1,const Fraction &f2);

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

using namespace std;

const string Fraction::doc {
    "目前仅支持分数对象的构造、输出、加/减/乘/除运算."
};

Fraction::Fraction(int x,int y):m1 {x},m2 {y} {
    simp();
}
Fraction::Fraction(const Fraction &f):m1 {f.m1},m2 {f.m2} {
    simp();
}
Fraction::~Fraction() {}

void Fraction::simp() {
    if (m2 < 0) {
        m1 = -m1;
        m2 = -m2;
    }
    bool sign = false;
    if (m1 < 0) sign = true;
    int t_m1 = abs(m1);
    for (int i = t_m1; i > 1; i--) {
        if (m2 % i == 0 && t_m1 % i == 0) {
            t_m1 /= i;
            m2 /= i;
            if (sign)
                m1 = -t_m1;
            else
                m1 = t_m1;
            return;
        }
    }
}
int Fraction::get_up() {
    return m1;
}

int Fraction::get_down() {
    return m2;
}

Fraction Fraction::negative() const {
    return Fraction(-m1,m2);
}

void output(const Fraction& f) {
     if (f.m1 == 0)
        cout << 0;
    else if (f.m2 == 0)
        cout << "分母不能为0";
    else if (f.m2==1)
        cout << f.m1;
    else
        cout << f.m1 << "/" << f.m2;
}

Fraction add(const Fraction &f1,const Fraction &f2) {
    int num = f1.m1 * f2.m2 + f2.m1 * f1.m2;
    int denom = f1.m2 * f2.m2;
    Fraction ff(num, denom);
    ff.simp();
    return ff;
}
Fraction sub(const Fraction &f1,const Fraction &f2) {
    int num = f1.m1 * f2.m2 - f2.m1 * f1.m2;
    int denom = f1.m2 * f2.m2;
    Fraction ff(num, denom);
    ff.simp();
    return ff;
}
Fraction mul(const Fraction &f1,const Fraction &f2) {
    Fraction ff(f1.m1*f2.m1,f1.m2*f2.m2);
    ff.simp();
    return ff;
}
Fraction div(const Fraction &f1,const Fraction &f2) {
    Fraction ff(f1.m1*f2.m2,f1.m2*f2.m1);
    ff.simp();
    return ff;
}

#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();
}

 

实验任务5：

account.h, account.cpp, 5_11.cpp源码，运行测试结果如下

//account.h
#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 data, double amount);
    double accumulate(int data)const {
        return accumulation + balance * (data - lastDate);
    }
public:
    SavingsAccount(int data, int id, double rate);
    int getId()const { return id; }
    double getBalance()const { return balance; }
    static double getTotal() { return total; }
    void deposit(int data, double amount);
    void withdraw(int data, double amount);
    void settle(int data);
    void show()const;
};
#endif//__ACCOUNT_H__

#include "account.h"
#include<iostream>
#include<cmath>
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 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:" << SavingsAccount::getTotal() << endl;
    return 0;
}