实验2 类和对象_基础编程1

1.实验任务1

t.h

 1 #pragma once
 2 
 3 #include<string>
 4 
 5  // 类T: 声明
 6  class T{
 7      public:
 8          T(int x=0,int y=0); // 普通构造函数
 9         T(const T &t); // 复制构造函数
10         T(T &&t); // 移动构造函数
11         ~T(); //析构函数
12         void adjust(int ratio); // 按系数成倍调整数据
13         void display() const;    // 以(m1, m2)形式显示T类对象信息
14         
15     private:
16          int m1,m2;
17          
18      // 类属性、方法
19     public:
20         static int get_cnt();   // 显示当前T类对象总数
21     
22     public:
23         static const std::string doc;  // 类T的描述信息
24         static const int max_cnt;  // 类T对象上限
25         
26     private:
27         static int cnt;  // 当前T类对象数目
28     
29     // 类T友元函数声明
30         friend void func();
31  };
32  
33  // 普通函数声明
34  void func();

t.cpp

 1 // 类T: 实现
 2 // 普通函数实现
 3 
 4 #include"t.h"
 5 #include<iostream>
 6 #include<string>
 7 
 8 using std::cout;
 9 using std::endl;
10 using std::string;
11 
12 // static成员数据类外初始化
13 const std::string T::doc{"a simple class sample"};
14 const int T::max_cnt=999;
15 int T::cnt=0;
16 
17 // 对象方法
18 T::T(int x,int y):m1{x},m2{y} {
19     ++cnt;
20     cout<<"T constructor called.\n";
21 }
22 
23 T::T(const T &t):m1{t.m1},m2{t.m2} {
24     ++cnt;
25     cout<<"T copy constructor called.\n";
26 }
27 
28 T::T(T &&t):m1{t.m1},m2{t.m2} {
29     ++cnt;
30     cout<<"T  move constructor called.\n";
31 }
32 
33 T::~T() {
34     --cnt;
35     cout<<"T destructor called.\n";
36 } 
37 
38 void T::adjust(int ratio) {
39     m1 *=ratio;
40     m2 *=ratio;
41 }
42 
43 void T::display() const {
44     cout<<"("<<m1<<","<<m2<<")";
45 }
46 
47 //类方法
48 int T::get_cnt() {
49     return cnt;
50 } 
51 
52 //友元
53 void func() {
54     T t5(42);
55     t5.m2=2049;
56     cout<<"t5= ";t5.display(); cout<<endl;
57 }

task1.cpp

 1 #include"t.h"
 2 #include<iostream>
 3 
 4 using std::cout;
 5 using std::endl;
 6 
 7 void test();
 8 
 9 int main() {
10     test();
11     cout<<"\nmain: \n";
12     cout<<"T objects'current count: "<<T::get_cnt()<<endl;
13 }
14 
15 void test() {
16     cout<<"test class T: \n";
17     cout<<"T info: "<<T::doc<<endl;
18     cout<<"T objects'max count: "<<T::max_cnt<<endl;
19     cout<<"T objects'current count: "<<T::get_cnt()<<endl<<endl;
20     
21     T t1;
22     cout<<"t1= "; t1.display(); cout<<endl;
23     
24     T t2(3,4);
25     cout<<"t2= "; t2.display(); cout<<endl;
26     
27     T t3(t2);
28     t3.adjust(2);
29     cout<<"t3= "; t3.display(); cout<<endl;
30     
31     T t4(std::move(t2));
32     cout<<"t3= "; t4.display(); cout<<endl;
33     
34     cout<<"T object'current count: "<<T::get_cnt()<<endl;
35     
36     func();
37 }

测试结果截图：

问题1：不能正确运行

原因：友元函数仅仅在类内声明，而缺少定义，编译器无法识别此函数

问题2：

普通构造函数功能：用于初始化对象的属性　　　　　　　　　　　　复制构造函数功能：通过复制已存在的对象来初始化新对象

　　　　　　调用时机：在创建对象时调用　　　　　　　　　　　　　　　　　　调用时机：当对象被复制时调用

移动构造函数功能：通过移动已存在的对象的资源来初始化新对象　　析构函数功能：清理对象占用的资源

　　　　　　调用时机：当对象被移动时调用　　　　　　　　　　　　　　　　　调用时机：对象超出作用域或动态分配内存被释放时调用

问题3：不能

2.实验任务2

Complex.h

 1 #pragma once
 2 #include<string>
 3 
 4 class Complex{
 5     public:
 6         static const std::string doc;
 7         
 8     private:
 9         double real,imag;
10         
11     public:
12         Complex(double x=0,double y=0);
13         Complex(const Complex &c);
14         
15         double get_real() const;
16         double get_imag() const;
17         void add(const Complex &c);
18         
19         friend Complex add(const Complex &c1,const Complex &c2);
20         friend bool is_equal(const Complex &c1,const Complex &c2);
21         friend bool is_not_equal(const Complex &c1,const Complex &c2);
22         friend void output(const Complex &c);
23         friend double abs(const Complex &c);
24 };
25 
26 Complex add(const Complex &c1,const Complex &c2);
27 bool is_equal(const Complex &c1,const Complex &c2);
28 bool is_not_equal(const Complex &c1,const Complex &c2);
29 void output(const Complex &c);
30 double abs(const Complex &c);

Complex.cpp

 1 #include "Complex.h"
 2 #include <iostream>
 3 #include<string>
 4 #include<cmath>
 5 
 6 using namespace std;
 7 
 8 const string Complex::doc{"a simplified complex class"};
 9 
10 Complex::Complex(double x,double y):real{x},imag{y} {}
11 Complex::Complex(const Complex &c):real{c.real},imag{c.imag} {}
12 
13 double Complex::get_real() const{
14     return real;
15 }
16 
17 double Complex::get_imag() const{
18     return imag;
19 }
20 
21 void Complex::add(const Complex &c){
22     real+=c.real;
23     imag+=c.imag;
24 }
25 
26 Complex add(const Complex &c1,const Complex &c2){
27     return Complex(c1.real+c2.real,c1.imag+c2.imag);
28 }
29 
30 bool is_equal(const Complex &c1,const Complex &c2){
31     return c1.real==c2.real&&c1.imag==c2.imag;
32 }
33 
34 bool is_not_equal(const Complex &c1,const Complex &c2){
35     return !is_equal(c1,c2);
36 }
37 
38 void output(const Complex &c){
39     cout<<c.real<<(c.imag>=0?"+":"")<<c.imag<<"i";
40 }
41 
42 double abs(const Complex &c){
43     return sqrt(c.real*c.real+c.imag*c.imag);
44 }

task2.cpp

 1 #include "Complex.h"
 2 #include <iostream>
 3 
 4 using std::cout;
 5 using std::endl;
 6 using std::boolalpha;
 7 
 8 void test() {
 9     cout << "类成员测试: " << endl;
10     cout << Complex::doc << endl;
11 
12     cout << endl;
13 
14     cout << "Complex对象测试: " << endl;
15     Complex c1;
16     Complex c2(3, -4);
17     const Complex c3(3.5);
18     Complex c4(c3);
19 
20     cout << "c1 = "; output(c1); cout << endl;
21     cout << "c2 = "; output(c2); cout << endl;
22     cout << "c3 = "; output(c3); cout << endl;
23     cout << "c4 = "; output(c4); cout << endl;
24     cout << "c4.real = " << c4.get_real() << ", c4.imag = " << c4.get_imag() << endl;
25 
26     cout << endl;
27 
28     cout << "复数运算测试: " << endl;
29     cout << "abs(c2) = " << abs(c2) << endl;
30     c1.add(c2);
31     cout << "c1 += c2, c1 = "; output(c1); cout << endl;
32     cout << boolalpha;
33     cout << "c1 == c2 : " << is_equal(c1, c2) << endl;
34     cout << "c1 != c3 : " << is_not_equal(c1, c3) << endl;
35     c4 = add(c2, c3);
36     cout << "c4 = c2 + c3, c4 = "; output(c4); cout << endl;
37 }
38 
39 int main() {
40     test();
41 }

测试结果截图：

3.实验任务3

 1 #include<iostream>
 2 #include<complex>
 3 
 4 using std::cout;
 5 using std::endl;
 6 using std::boolalpha;
 7 using std::complex;
 8 
 9 void test(){
10     cout<<"标准库模板类complex测试："<<endl;
11     complex<double>c1;
12     complex<double>c2(3,-4);
13     const complex<double>c3(3.5);
14     complex<double> c4(c3);
15     
16     cout<<"c1= "<<c1<<endl;
17     cout<<"c2= "<<c2<<endl;
18     cout<<"c3= "<<c3<<endl;
19     cout<<"c4= "<<c3<<endl;
20     cout<<"c4.real = "<<c4.real()<<",c4.imag = "<<c4.imag()<<endl;
21     cout<<endl;
22     
23     cout<<"复数运算测试："<<endl;
24     cout<<"abs(c2) = "<<abs(c2)<<endl;
25     c1+=c2;
26     cout<<"c1+=c2,c1 = "<<c1<<endl;
27     cout<<boolalpha;
28     cout<<"c1==c2 : "<<(c1==c2)<<endl;
29     cout<<"c1!=c3 : "<<(c1!=c3)<<endl;
30     c4=c2+c3;
31     cout<<"c4=c2+c3,c4 = "<<c4<<endl; 
32 }
33 
34 int main(){
35     test();
36 }

测试结果截图：

使用的接口：

std::Complex的构造函数
成员函数c.real() c.imag()
abs()
c1+=c2
c4=c2+c3
c1==c2 c1!=c3

对比(Q1):

std::complex 中，直接支持了运算符的重载（ +, -, ==, !=），方便基本运算和比较操作，无需额外定义
可以调用real() 和 imag() 成员函数，直接访问实部和虚部
std::complex 的构造更加简单，可以直接用实数初始化
可以直接通过 cout 输出，不需要定义输出函数output()

　　(Q2):

设计类时，可以考虑重载标准运算符，以简化运算
使用标准模板库类可以使代码更简洁

4.实验任务4

Fraction.h

 1 #pragma once
 2 #include<iostream>
 3 #include<string>
 4 
 5 using namespace std;
 6 
 7 class Fraction{
 8     public:
 9         static const string doc;
10         static int gys(int a,int b);
11         
12     private:
13         int up,down;
14         
15     public:
16         Fraction(int x);
17         Fraction(int x,int y);
18         Fraction(const Fraction &f);
19         
20         void simplify();
21         int get_up() const;
22         int get_down() const;
23         Fraction negative();
24         
25         friend void output(const Fraction &f);
26         friend Fraction add(const Fraction &f1,const Fraction &f2);
27         friend Fraction sub(const Fraction &f1,const Fraction &f2);
28         friend Fraction mul(const Fraction &f1,const Fraction &f2);
29         friend Fraction div(const Fraction &f1,const Fraction &f2);
30 };
31 void output(const Fraction &f);
32 Fraction add(const Fraction &f1,const Fraction &f2);
33 Fraction sub(const Fraction &f1,const Fraction &f2);
34 Fraction mul(const Fraction &f1,const Fraction &f2);
35 Fraction div(const Fraction &f1,const Fraction &f2);

Fraction.cpp

 1 #include<iostream>
 2 #include<string>
 3 #include"Fraction.h"
 4 
 5 using namespace std;
 6 
 7 const 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."};
 8 
 9 int Fraction::gys(int a,int b){
10     while(b){
11         int t=a%b;
12         a=b;
13         b=t;
14     }
15     return a;
16 }
17 
18 void Fraction::simplify(){
19     int r=Fraction::gys(up,down);
20     up/=r;
21     down/=r;
22     if(down<0){
23         up=-up;
24         down=-down;
25     }
26 }
27 
28 Fraction::Fraction(int x):up{x},down{1} {simplify();}
29 Fraction::Fraction(int x,int y):up{x},down{y} {simplify();}
30 Fraction::Fraction(const Fraction &f):up{f.up},down{f.down} {}
31 
32 
33 int Fraction::get_up() const{
34     return up;
35 }
36 
37 int Fraction::get_down() const{
38     return down;
39 }
40 
41 Fraction Fraction::negative(){
42     return Fraction(-up,down);
43 }
44 
45 void output(const Fraction &f){
46     if(f.get_down()==1||f.get_up()==0)
47         cout<<f.get_up();
48     else if(f.get_down()==0)
49         cout<<"分母不能为0";
50     else
51         cout<<f.get_up()<<"/"<<f.get_down();
52 }
53     
54 Fraction add(const Fraction &f1,const Fraction &f2){
55     return Fraction(f1.up*f2.down+f2.up*f1.down,f1.down*f2.down);
56 }
57 
58 Fraction sub(const Fraction &f1,const Fraction &f2){
59     return Fraction(f1.up*f2.down-f2.up*f1.down,f1.down*f2.down);
60 }
61 
62 Fraction mul(const Fraction &f1,const Fraction &f2){
63     return Fraction(f1.up*f2.up,f1.down*f2.down);
64 }
65 
66 Fraction div(const Fraction &f1,const Fraction &f2){
67     return Fraction(f1.up*f2.down,f1.down*f2.up);
68 }

task4.cpp

 1 #include "Fraction.h"
 2 #include <iostream>
 3 
 4 using std::cout;
 5 using std::endl;
 6 
 7 
 8 void test1() {
 9     cout << "Fraction类测试: " << endl;
10     cout << Fraction::doc << endl << endl;
11 
12     Fraction f1(5);
13     Fraction f2(3, -4), f3(-18, 12);
14     Fraction f4(f3);
15     cout << "f1 = "; output(f1); cout << endl;
16     cout << "f2 = "; output(f2); cout << endl;
17     cout << "f3 = "; output(f3); cout << endl;
18     cout << "f4 = "; output(f4); cout << endl;
19 
20     Fraction f5(f4.negative());
21     cout << "f5 = "; output(f5); cout << endl;
22     cout << "f5.get_up() = " << f5.get_up() << ", f5.get_down() = " << f5.get_down() << endl;
23 
24     cout << "f1 + f2 = "; output(add(f1, f2)); cout << endl;
25     cout << "f1 - f2 = "; output(sub(f1, f2)); cout << endl;
26     cout << "f1 * f2 = "; output(mul(f1, f2)); cout << endl;
27     cout << "f1 / f2 = "; output(div(f1, f2)); cout << endl;
28     cout << "f4 + f5 = "; output(add(f4, f5)); cout << endl;
29 }
30 
31 void test2() {
32     Fraction f6(42, 55), f7(0, 3);
33     cout << "f6 = "; output(f6); cout << endl;
34     cout << "f7 = "; output(f7); cout << endl;
35     cout << "f6 / f7 = "; output(div(f6, f7)); cout << endl;
36 }
37 
38 int main() {
39     cout << "测试1: Fraction类基础功能测试\n";
40     test1();
41 
42     cout << "\n测试2: 分母为0测试: \n";
43     test2();
44 }

测试结果截图：

5.实验任务5

account.h

 1 #ifndef __ACCOUNT_H__
 2 #define __ACCOUNT_H__
 3 class SavingsAccount{
 4 private:
 5     int id;
 6     double balance;
 7     double rate;
 8     int lastDate;
 9     double accumulation;
10     static double total;
11     void record(int date, double amount);
12     double accumulate(int date) const {
13         return accumulation + balance * (date - lastDate);
14     }
15 public:
16         SavingsAccount(int date, int id, double rate); int getId() const { return id; }
17         double getBalance() const { return balance; }
18         double getRate() const { return rate; }
19         static double getTotal() { return total; }
20         void deposit(int date, double amount);
21         void withdraw(int date, double amount);
22         void settle(int date);
23         void show() const;
24     };
25 #endif//_ACCOUNT_H

account.cpp

 1 #include "account.h"
 2 #include <cmath>
 3 #include <iostream>
 4 using namespace std;
 5 double SavingsAccount::total = 0;
 6 SavingsAccount::SavingsAccount(int date, int id, double rate)
 7     : id(id), balance(0), rate(rate), lastDate(date),
 8     accumulation(0) {
 9     cout << date << "\t#" << id << " is created" << endl;
10 }
11         void SavingsAccount::record(int date, double amount) {
12         accumulation = accumulate(date);
13         lastDate = date;
14         amount = floor(amount * 100+ 0.5) / 100;
15         balance += amount;
16         total += amount;
17         cout << date << "\t#" << id << "\t" << amount << "\t" <<
18             balance << endl;
19         }
20 
21             void SavingsAccount::deposit(int date, double amount) {
22             record(date, amount);
23         }
24         void SavingsAccount::withdraw(int date, double amount) {
25             if (amount > getBalance())
26                 cout << "Error: not enough money" << endl;
27             else
28                 record(date, -amount);
29         }
30         void SavingsAccount::settle(int date) {
31                 double interest = accumulate(date) * rate / 365;
32             if (interest != 0)
33                 record(date, interest);
34             accumulation = 0;
35         }
36         void SavingsAccount::show() const {
37             cout << "#" << id << "\tBalance: " << balance;
38         }

5_11.cpp

 1 #include "account.h"
 2 #include <iostream>
 3 using namespace std;
 4 int main() {
 5     SavingsAccount sa0(1, 21325302, 0.015);
 6     SavingsAccount sa1(1, 58320212, 0.015);
 7     sa0.deposit(5, 5000);
 8     sa1.deposit(25, 10000);
 9     sa0.deposit(45, 5500);
10     sa1.withdraw(60, 4000);
11     sa0.settle(90);
12     sa1.settle(90);
13     sa0.show(); cout << endl;
14     sa1.show(); cout << endl;
15     cout << "Total: " << SavingsAccount::getTotal() << endl;
16     return 0;
17 }

测试结果截图：

合理，改进建议：

可以用 std::round 来实现四舍五入
settle 方法中的 365 可以定义为一个常量，以提高可读性
可以提供一个初始余额作为参数来初始化balance

posted @ 2024-10-24 14:22 lbldmx 阅读(12) 评论(0) 编辑收藏举报

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实验2 类和对象_基础编程1

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