实验2 类和对象_基础编程1

实验任务1：

 1 #pragma once
 2 #include <string>
 3 
 4 class T {
 5     public:
 6         T(int x = 0, int y = 0);
 7         T(const T &t);
 8         T(T &&t);
 9         ~T();
10 
11         void adjust(int ratio);
12         void display() const;
13     private:
14         int m1, m2;
15 
16     public:
17         static int get_cnt();
18     public:
19         static const std::string doc;
20         static const int max_cnt;
21     private:
22         static int cnt;
23         friend void func();
24 };
25 void func();
t.h
 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 
18 // 对象方法
19 T::T(int x, int y): m1{x}, m2{y} { 
20     ++cnt; 
21     cout << "T constructor called.\n";
22 } 
23 
24 T::T(const T &t): m1{t.m1}, m2{t.m2} {
25     ++cnt;
26     cout << "T copy constructor called.\n";
27 }
28 
29 T::T(T &&t): m1{t.m1}, m2{t.m2} {
30     ++cnt;
31     cout << "T move constructor called.\n";
32 }    
33 
34 T::~T() {
35     --cnt;
36     cout << "T destructor called.\n";
37 }           
38 
39 void T::adjust(int ratio) {
40     m1 *= ratio;
41     m2 *= ratio;
42 }    
43 
44 void T::display() const {
45     cout << "(" << m1 << ", " << m2 << ")" ;
46 }     
47 
48 // 类方法
49 int T::get_cnt() {
50    return cnt;
51 }
52 
53 // 友元
54 void func() {
55     T t5(42);
56     t5.m2 = 2049;
57     cout << "t5 = "; t5.display(); cout << endl;
58 }
t.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 
22     T t1;
23     cout << "t1 = "; t1.display(); cout << endl;
24 
25     T t2(3, 4);
26     cout << "t2 = "; t2.display(); cout << endl;
27 
28     T t3(t2);
29     t3.adjust(2);
30     cout << "t3 = "; t3.display(); cout << endl;
31 
32     T t4(std::move(t2));
33     cout << "t3 = "; t4.display(); cout << endl;
34 
35     cout << "T objects'current count: " << T::get_cnt() << endl;
36 
37     func();
38 }
task1.cpp

运行结果截图：

回答问题：

问题1：

t.h中，普通函数 func 作为类X的友元，在类的内部声明了友元关系。在类外部，去掉 line36，重新编译，是否能正确运行。如果能，回答说明可以去掉line36。如果不能，以截图 形式给出编译报错信息，分析可能的原因。

答：不能。去掉则没有对func()函数进行声明，导致函数运行失败。

问题2：t.h中，line9-12给出了各种构造函数、析构函数。总结各种构造函数的功能，以及它们与析 构函数的调用时机。 

答：普通构造函数：用于初始化对象的状态和属性。对象创建时自动调用普通构造函数进行初始化。

复制构造函数：用于创建对象时复制已有对象。对象以已有对象初始化时调用复制构造函数。

移动构造函数：用于“窃取”另一个对象的资源，而不是复制他们，提高性能。对象以右值初始化时调用移动构造函数。
析构函数：在对象生命周期结束时自动调用的函数，用于执行清理工作，如释放动态分配的内存。

问题3：t.cpp中，line13-15，调整到t.h，重新编译，程序能否正确编译运行

答：不能。

实验任务2：

代码：

 1 #pragma once
 2 #include <string>
 3 #include "Complex.h"
 4 
 5 class Complex {
 6     public:
 7         Complex(double r = 0, double i = 0);
 8         Complex(const Complex &c);
 9         ~ Complex();
10 
11         void add(const Complex &c);
12     private:
13         double real;
14         double imag;
15 
16     public:
17         double get_real() const;
18         double get_imag() const;
19 
20     public:
21         friend Complex add(const Complex &c1, const Complex &c2);
22         friend bool is_equal(const Complex &c1, const Complex &c2);
23         friend bool is_not_equal(const Complex &c1, const Complex &c2);
24         friend void output(const Complex &c);
25         friend double abs(const Complex &c);
26 
27     public:
28         static const std::string doc;
29 
30 };
Complex.h
 1 #include "Complex.h"
 2 #include<iostream>
 3 #include<string>
 4 #include<cmath>
 5 
 6 using namespace std;
 7 
 8 const string Complex::doc {
 9     "a simplified complex class"
10 };
11 
12 Complex::Complex(double r,double i):real {r},imag {i} {}
13 Complex::Complex(const Complex &c):real {c.real},imag {c.imag} {}
14 Complex::~Complex() {}
15 
16 void Complex::add(const Complex &c) {
17     real +=c.real;
18     imag +=c.imag;
19 }
20 
21 double Complex::get_real() const{
22     return real;
23 }
24 double Complex::get_imag() const{
25     return imag;
26 }
27 
28 Complex add(const Complex &c1,const Complex &c2) {
29     return Complex(c1.real + c2.real, c1.imag + c2.imag);
30 }
31 bool is_equal(const Complex &c1,const Complex &c2) {
32     if(c1.real==c2.real&&c1.imag==c2.imag)return true;
33     else return false;
34 
35 }
36 bool is_not_equal(const Complex &c1,const Complex &c2) {
37     if(c1.real==c2.real&&c1.imag==c2.imag)return false;
38     else return true;
39 
40 }
41 void output(const Complex &c) {
42     if(c.imag<0) {
43         cout<<c.real<<"-"<<c.imag*(-1)<<"i";
44     } else {
45         cout<<c.real<<"+"<<c.imag<<"i";
46     }
47 }
48 double abs(const Complex &c) {
49     return sqrt(c.real*c.real+c.imag*c.imag);
50 }
Complex.cpp
 1 #include <iostream>
 2 #include "Complex.h"
 3 #include <string>
 4 
 5 using std::cout;
 6 using std::endl;
 7 using std::boolalpha;
 8 void test() {
 9     cout << "类成员测试: " << endl;
10     cout << Complex::doc << endl;
11     cout << endl;
12     cout << "Complex对象测试: " << endl;
13     Complex c1;
14     Complex c2(3, -4);
15     const Complex c3(3.5);
16     Complex c4(c3);
17     cout << "c1 = ";
18     output(c1);
19     cout << endl;
20     cout << "c2 = ";
21     output(c2);
22     cout << endl;
23     cout << "c3 = ";
24     output(c3);
25     cout << endl;
26     cout << "c4 = ";
27     output(c4);
28     cout << endl;
29     cout << "c4.real = " << c4.get_real() << ", c4.imag = " << c4.get_imag()
30          << endl;
31     cout << endl;
32     cout << "复数运算测试: " << endl;
33     cout << "abs(c2) = " << abs(c2) << endl;
34     c1.add(c2);
35     cout << "c1 += c2, c1 = ";
36     output(c1);
37     cout << endl;
38     cout << boolalpha;
39     cout << "c1 == c2 : " << is_equal(c1, c2) << endl;
40     cout << "c1 != c3 : " << is_not_equal(c1, c3) << endl;
41     c4 = add(c2, c3);
42     cout << "c4 = c2 + c3, c4 = ";
43     output(c4);
44     cout << endl;
45 }
46 int main() {
47     test();
48 }
task2.cpp

运行结果：

实验任务3：

代码：

 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comple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 = " << c4 << 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 }
task3.cpp

运行结果：

问题：1. 观察使用标准库模板类进行复数运算与输出时，代码比任务2的测试代码，哪些地方代码写法 不同/代码更简洁 2. 思考标准库模板类Complex的设计，与任务2对比，你是否有所启发 。

答：使用标准模板库类Complex的设计运行效率高，代码更加简洁明了。

实验任务4：

 1 #pragma once
 2 #include<iostream>
 3 #include<string>
 4 
 5 using namespace std;
 6 
 7 class Fraction{
 8     public:
 9         Fraction(int x,int y = 1);
10         Fraction(const Fraction &f);
11         ~Fraction();
12 
13     private:
14         int up;
15         int down;
16     public:
17         int get_up() const;
18         int get_down() const;
19         Fraction negative();
20         Fraction simplify();
21 
22     public:
23         static const string doc;
24         friend void output(const Fraction &f);
25         friend Fraction add(const Fraction &f1,const Fraction &f2);
26         friend Fraction sub(const Fraction &f1,const Fraction &f2);
27         friend Fraction mul(const Fraction &f1,const Fraction &f2);
28         friend Fraction div(const Fraction &f1,const Fraction &f2);
29 
30 };
31 void output(const Fraction& f1);
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);
Complex.h
  1 include <iostream>
  2 #include <string>
  3 #include "Fraction.h"
  4 
  5 using std::cout;
  6 using std::endl;
  7 using std::string;
  8 
  9 const string Fraction::doc{
 10     "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."
 11 };
 12 
 13 Fraction::Fraction(int x,int y):up{x},down{y}{}
 14 Fraction::Fraction(const Fraction &f):up{f.up},down{f.down}{}
 15 Fraction::~Fraction(){}
 16 
 17 
 18 int Fraction::get_up() const{
 19     return up;
 20 }
 21 
 22 int Fraction::get_down() const{
 23     return down;
 24 }
 25 
 26 Fraction Fraction::negative() {
 27     Fraction t = simplify();
 28     return Fraction(-t.up,t.down);
 29 }
 30 
 31 Fraction Fraction::simplify()
 32 {
 33     int m, x, y, z;
 34     if (up >= 0)
 35     {
 36         x = up;
 37         if (down > 0)
 38         {
 39             y = down;
 40             z = 1;
 41         }
 42         else
 43         {
 44             y = -down;
 45             z = -1;
 46         }
 47     }
 48     else
 49     {
 50         x = -up;
 51         if (down > 0)
 52         {
 53             y = down;
 54             z = -1;
 55         }
 56         else
 57         {
 58             y = -down;
 59             z = 1;
 60         }
 61     }
 62     if (x > y)
 63         m= y;
 64     else
 65         m= x;
 66     for (int i = m; i >= 1; i--)
 67         if (x % i == 0 && y % i == 0)
 68         {
 69             x = x / i;
 70             y = y / i;
 71             break;
 72         }
 73     if (z == 1)
 74         return Fraction(x, y);
 75     return Fraction(-x, y);
 76 }
 77 
 78 void output(const Fraction& f){
 79     Fraction t = Fraction(f.up,f.down);
 80     t = t.simplify();
 81     if(t.down == 0) cout << "分母不能为0";
 82     else {
 83         if(t.up == 0)
 84         cout << "0";
 85     else if(t.up != 0 && t.down == 1)
 86         cout << t.up;
 87     else
 88          cout << t.up << "/" << t.down;
 89     cout << endl;
 90     }
 91 }
 92 Fraction add(const Fraction &f1,const Fraction &f2) {
 93     int num = f1.up * f2.down + f2.up * f1.down;
 94     int denom = f1.down * f2.down;
 95     return Fraction(num, denom);
 96 }
 97 Fraction sub(const Fraction &f1,const Fraction &f2) {
 98     int num = f1.up * f2.down - f2.up * f1.down;
 99     int denom = f1.down * f2.down;
100     return Fraction(num, denom);
101 }
102 Fraction mul(const Fraction &f1,const Fraction &f2) {
103     return Fraction(f1.up*f2.up,f1.down*f2.down);
104 
105 }
106 Fraction div(const Fraction &f1,const Fraction &f2) {
107     return Fraction(f1.up*f2.down,f1.down*f2.up);
108 
109 }
Fraction.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 }
task4.cpp

运行结果：

 实验任务5：

代码：

 1 #pragma once
 2 #ifndef  ACCOUNT_H
 3 #define  ACCOUNT_H
 4 class SavingsAccount {
 5     private:
 6         int id;
 7         double balance;
 8         double rate;
 9         int lastDate;
10         double accumulation;
11         static double total;
12 
13         void record(int date, double amount);
14         double accumulate(int date)const {
15             return accumulation + balance * (date - lastDate);
16         }
17 
18 
19     public:
20         SavingsAccount(int date, int id, double rate);
21         int getId()const {
22             return id;
23         }
24         double getBanlance()const {
25             return balance;
26         }
27         double getRate()const {
28             return rate;
29         }
30         static double getTotal() {
31             return total;
32         }
33         void deposit(int date, double amcount);
34         void withdraw(int date, double amount);
35         void settle(int date);
36         void show()const;
37 };
account.h
 1 #include"account.h"
 2 #include<cmath>
 3 #include<iostream>
 4 using namespace std;
 5 
 6 double SavingsAccount::total = 0;
 7 
 8 SavingsAccount::SavingsAccount(int date, int id, double rate):id(id), balance(0), rate(rate), lastDate(date), accumulation(0) {
 9     cout << date << "\t#" << id << "       is created" << endl;
10 }
11 
12 void SavingsAccount::record(int date, double amount) {
13     accumulation = accumulate(date);
14     lastDate = date;
15     amount = floor(amount * 100 + 0.5) / 100;
16     balance += amount;
17     total += amount;
18     cout << date << "\t#" << id << "\t" << amount << "\t" << balance << endl;
19 }
20 
21 void SavingsAccount::deposit(int date, double amount) {
22     record(date, amount);
23 }
24 
25 void SavingsAccount::withdraw(int date, double amount) {
26     if (amount > getBanlance())
27         cout << "Error: not enough money" << endl;
28     else
29         record(date, -amount);
30 }
31 
32 void SavingsAccount::settle(int date) {
33     double interest = accumulate(date) * rate / 365;
34     if (interest != 0)
35         record(date, interest);
36     accumulation = 0;
37 }
38 
39 void SavingsAccount::show()const {
40     cout << "#" << id << "\tBalance:" << balance;
41 }
account.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 
 8     sa0.deposit(5, 5000);
 9     sa1.deposit(25, 10000);
10     sa0.deposit(45, 5500);
11     sa1.withdraw(60, 4000);
12 
13     sa0.settle(90);
14     sa1.settle(90);
15 
16     sa0.show(); cout << endl;
17     sa1.show(); cout << endl;
18     cout << "Total:" << SavingsAccount::getTotal() << endl;
19     return 0;
20 }
task5.cpp

运行结果：

 

posted @ 2024-10-30 00:33  kiddings  阅读(4)  评论(0)  编辑  收藏  举报