实验二
实验一代码：
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 } 39 40 // 类T: 实现 41 // 普通函数实现 42 43 #include "t.h" 44 #include <iostream> 45 #include <string> 46 47 using std::cout; 48 using std::endl; 49 using std::string; 50 51 // static成员数据类外初始化 52 const std::string T::doc{"a simple class sample"}; 53 const int T::max_cnt = 999; 54 int T::cnt = 0; 55 56 57 // 对象方法 58 T::T(int x, int y): m1{x}, m2{y} { 59 ++cnt; 60 cout << "T constructor called.\n"; 61 } 62 63 T::T(const T &t): m1{t.m1}, m2{t.m2} { 64 ++cnt; 65 cout << "T copy constructor called.\n"; 66 } 67 68 T::T(T &&t): m1{t.m1}, m2{t.m2} { 69 ++cnt; 70 cout << "T move constructor called.\n"; 71 } 72 73 T::~T() { 74 --cnt; 75 cout << "T destructor called.\n"; 76 } 77 78 void T::adjust(int ratio) { 79 m1 *= ratio; 80 m2 *= ratio; 81 } 82 83 void T::display() const { 84 cout << "(" << m1 << ", " << m2 << ")" ; 85 } 86 87 // 类方法 88 int T::get_cnt() { 89 return cnt; 90 } 91 92 // 友元 93 void func() { 94 T t5(42); 95 t5.m2 = 2049; 96 cout << "t5 = "; t5.display(); cout << endl; 97 } 98 99 #pragma once 100 101 #include <string> 102 103 // 类T: 声明 104 class T { 105 // 对象属性、方法 106 public: 107 T(int x = 0, int y = 0); // 普通构造函数 108 T(const T &t); // 复制构造函数 109 T(T &&t); // 移动构造函数 110 ~T(); // 析构函数 111 112 void adjust(int ratio); // 按系数成倍调整数据 113 void display() const; // 以(m1, m2)形式显示T类对象信息 114 115 private: 116 int m1, m2; 117 118 // 类属性、方法 119 public: 120 static int get_cnt(); // 显示当前T类对象总数 121 122 public: 123 static const std::string doc; // 类T的描述信息 124 static const int max_cnt; // 类T对象上限 125 126 private: 127 static int cnt; // 当前T类对象数目 128 129 // 类T友元函数声明 130 friend void func(); 131 }; 132 133 // 普通函数声明 134 void func();
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问题1：
不能，func（）函数未声明，所以不存在该友元函数
问题2：构造函数的作用就是在对象被创建时利用特定的值构造对象，将对象初始化为一个特定的状态。1.复制构造函数：其形参是本类的对象的引用。
其作用是使用一个已经存在的对象（由复制构造函数的参数指定），去初始化同类的一个新对象。。2.移动构造函数：左值是位于赋值语句左侧的对象
变量，右值是赋值语句右侧的值，不依附于对象。3.所有构造函数调用完后，析构函数依次调用。
问题3：
不能
实验二代码：
1 #pragma once 2 3 #include<string> 4 5 6 class Complex{ 7 public: 8 Complex (double a=0, double b=0); 9 Complex (const Complex &c); friend void output(const Complex &c); 10 const double get_real(); 11 const double get_imag(); 12 friend double abs(const Complex &c); 13 friend bool is_equal(const Complex &c1, const Complex &c2); 14 friend bool is_not_equal(const Complex &c1, const Complex &c2); 15 friend Complex add(const Complex &c1, const Complex &c2); 16 Complex add(const Complex &c); 17 static std::string doc; 18 ~Complex(); 19 private: 20 double real,imag; 21 22 }; 23 void output(const Complex &c); 24 double abs(const Complex &c); 25 bool is_equal(const Complex &c1, const Complex &c2); 26 bool is_not_equal(const Complex &c1, const Complex &c2); 27 Complex add(const Complex &c1, const Complex &c2); 28 29 30 31 32 #include "Complex.h" 33 #include<iostream> 34 #include<string> 35 #include<cmath> 36 37 using namespace std; 38 39 Complex::Complex(double a,double b): real{a},imag{b}{} 40 Complex::Complex(const Complex &c){ 41 real=c.real; 42 imag=c.imag; 43 } 44 Complex add(const Complex &c1,const Complex &c2){ 45 Complex c; 46 c.real=c1.real+c2.real; 47 c.imag=c1.imag+c2.imag; 48 return c; 49 } 50 Complex Complex::add(const Complex &c){ 51 real+=c.real; 52 imag+=c.imag; 53 } 54 const double Complex::get_real(){ 55 return real; 56 } 57 const double Complex::get_imag(){ 58 return imag; 59 } 60 double abs(const Complex &c){ 61 double a=0; 62 a=c.real*c.real+c.imag*c.imag; 63 a=sqrt(a); 64 } 65 bool is_equal(const Complex &c1,const Complex &c2){ 66 if(c1.real==c2.real && c1.imag==c2.imag) 67 return 1; 68 else 69 return 0; 70 } 71 bool is_not_equal(const Complex &c1,const Complex &c2){ 72 if(c1.real!=c2.real || c1.imag!=c2.imag) 73 return 1; 74 else 75 return 0; 76 } 77 Complex::~Complex()=default; 78 string Complex::doc="a simplified Complex class"; 79 void output(const Complex &c){ 80 if(c.imag<0) 81 cout<<c.real<<c.imag<<"i"; 82 else 83 cout<<c.real<<"+"<<c.imag<<"i"; 84 }
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实验三代码：
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 }
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实验四代码：
1 #include "Fraction.h" 2 3 #include<iostream> 4 5 using namespace std; 6 7 Fraction::Fraction(int a,int b):up{a},down{b}{} 8 Fraction::Fraction(const Fraction &f){ 9 up=f.up; 10 down=f.down; 11 } 12 Fraction Fraction::negative(){ 13 Fraction f; 14 f.up=up*-1; 15 f.down=down; 16 return f; 17 } 18 Fraction::~Fraction()=default; 19 int Fraction::get_down(){ 20 int a,b,c,d,e; 21 a=up; 22 b=down; 23 d=up; 24 e=down; 25 while(b!=0) 26 { 27 c=b; 28 b=a%b; 29 a=c; 30 } 31 d=d/a; 32 e=e/a; 33 return e; 34 } 35 int Fraction::get_up(){ 36 int a,b,c,d,e; 37 a=up; 38 b=down; 39 d=up; 40 e=down; 41 while(b!=0) 42 { 43 c=b; 44 b=a%b; 45 a=c; 46 } 47 d=d/a; 48 e=e/a; 49 return d; 50 } 51 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."; 52 Fraction add(const Fraction &f1,const Fraction &f2){ 53 Fraction f; 54 f.down=f1.down*f2.down; 55 f.up=f1.up*f2.down+f2.up*f1.down; 56 return f; 57 } 58 Fraction sub(const Fraction &f1,const Fraction &f2){ 59 Fraction f; 60 f.down=f1.down*f2.down; 61 f.up=f1.up*f2.down-f2.up*f1.down; 62 return f; 63 } 64 Fraction mul(const Fraction &f1,const Fraction &f2){ 65 Fraction f; 66 f.down=f1.down*f2.down; 67 f.up=f1.up*f2.up; 68 return f; 69 } 70 Fraction div(const Fraction &f1,const Fraction &f2){ 71 Fraction f; 72 f.down=f1.down*f2.up; 73 f.up=f1.up*f2.down; 74 return f; 75 } 76 void output(const Fraction &f){ 77 int a,b,c,d,e; 78 if(f.down==0) 79 cout<<"分母不能为0"; 80 else 81 { 82 a=f.up; 83 b=f.down; 84 d=f.up; 85 e=f.down; 86 while(b!=0) 87 { 88 c=b; 89 b=a%b; 90 a=c; 91 } 92 d=d/a; 93 e=e/a; 94 if(e==1) 95 cout<<d; 96 else if(e<0) 97 cout<<d*-1<<"/"<<e*-1; 98 else 99 cout<<d<<"/"<<e; 100 } 101 } 102 103 104 105 106 #pragma once 107 108 #include<string> 109 class Fraction{ 110 public: 111 Fraction(int a=1,int b=1); 112 Fraction(const Fraction &f); 113 int get_up(); 114 int get_down(); 115 Fraction negative(); 116 static std::string doc; 117 friend void output(const Fraction &f); 118 friend Fraction add(const Fraction &f1,const Fraction &f2); 119 friend Fraction sub(const Fraction &f1,const Fraction &f2); 120 friend Fraction mul(const Fraction &f1,const Fraction &f2); 121 friend Fraction div(const Fraction &f1,const Fraction &f2); 122 ~Fraction(); 123 private: 124 int up,down; 125 }; 126 void output(const Fraction &f); 127 Fraction add(const Fraction &f1,const Fraction &f2); 128 Fraction sub(const Fraction &f1,const Fraction &f2); 129 Fraction mul(const Fraction &f1,const Fraction &f2); 130 Fraction div(const Fraction &f1,const Fraction &f2);
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实验五代码：
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) :id(id), balance(0), rate(rate), lastDate(date), accumulation(0) { 7 cout << date << "\t#" << id << "is created" << endl; 8 } 9 void SavingsAccount::record(int date, double amount) { 10 accumulation = accumulate(date); 11 lastDate = date; 12 amount = floor(amount * 100 + 0.5) / 100; 13 balance += amount; 14 total += amount; 15 cout << date << "\t#" << id << "\t" << amount << "\t" << balance << endl; 16 } 17 void SavingsAccount::deposit(int date, double amount) { 18 record(date, amount); 19 } 20 void SavingsAccount::withdraw(int date,double amount) { 21 if (amount > getBalance()) 22 cout << "Error:not enough money" << endl; 23 else { 24 record(date, -amount); 25 } 26 } 27 void SavingsAccount::settle(int date) { 28 double interest = accumulate(date) * rate / 365; 29 if (interest != 0) 30 record(date, interest); 31 accumulation = 0; 32 } 33 void SavingsAccount::show()const { 34 cout << "#" << id << "\tBalance:" << balance; 35 } 36 37 38 39 #include"account.h" 40 #include<iostream> 41 using namespace std; 42 int main() { 43 SavingsAccount sa0(1, 21325302, 0.015); 44 SavingsAccount sa1(1, 58320212, 0.015); 45 sa0.deposit(5, 5000); 46 sa1.deposit(25, 10000); 47 sa0.deposit(45, 5500); 48 sa1.withdraw(60, 4000); 49 sa0.settle(90); 50 sa1.settle(90); 51 sa0.show(); cout << endl; 52 sa1.show(); cout << endl; 53 cout << "Total: " << SavingsAccount::getTotal() << endl; 54 return 0; 55 } 56 57 58 59 60 #pragma once 61 class SavingsAccount { 62 private: 63 int id; 64 double balance; 65 double rate; 66 int lastDate; 67 double accumulation; 68 static double total; 69 void record(int date, double amount); 70 double accumulate(int date) const { 71 return accumulation + balance * (date - lastDate); 72 } 73 public: 74 SavingsAccount(int date, int id, double rate); 75 int getId()const { return id; } 76 double getBalance()const { return balance; } 77 double getRate()const { return rate; } 78 static double getTotal() { return total; } 79 void deposit(int date, double amount); 80 void withdraw(int date, double amount); 81 void settle(int date); 82 83 void show()const; 84 };
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