task1
1 #pragma once
2
3 #include <string>
4
5 // 类T: 声明
6 class T {
7 // 对象属性、方法
8 public:
9 T(int x = 0, int y = 0); // 普通构造函数
10 T(const T &t); // 复制构造函数
11 T(T &&t); // 移动构造函数
12 ~T(); // 析构函数
13
14 void adjust(int ratio); // 按系数成倍调整数据
15 void display() const; // 以(m1, m2)形式显示T类对象信息
16
17 private:
18 int m1, m2;
19
20 // 类属性、方法
21 public:
22 static int get_cnt(); // 显示当前T类对象总数
23
24 public:
25 static const std::string doc; // 类T的描述信息
26 static const int max_cnt; // 类T对象上限
27
28 private:
29 static int cnt; // 当前T类对象数目
30
31 // 类T友元函数声明
32 friend void func();
33 };
34
35 // 普通函数声明
36 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
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
1 #ifndef COMPLEX_H
2 #define COMPLEX_H
3 #include<string>
4 #include<iostream>
5 #include<cmath>
6 class Complex{
7 public:
8 static const std::string doc;
9
10 Complex();
11
12 Complex(double real);
13
14 Complex(double real,double imag);
15
16 Complex(const Complex& other);
17
18 double get_real()const;
19
20 double get_imag()const;
21
22 void add(const Complex& other);
23
24 friend Complex add(const Complex& c1,const Complex& c2);
25 friend bool is_equal(const Complex& c1,const Complex& c2);
26 friend bool is_not_equal(const Complex& c1,const Complex& c2);
27 friend void output(const Complex& c);
28 friend double abs(const Complex& c);
29
30 private:
31 double real;
32 double imag;
33 };
34 #endif
Complex.h
1 #include"Complex.h"
2
3 const std::string Complex::doc="a simplified Complex class";
4
5 Complex::Complex():real(0.0),imag(0.0){}
6
7 Complex::Complex(double real):real(real),imag(0.0){}
8
9 Complex::Complex(double real,double imag):real(real),imag(imag){}
10
11 Complex::Complex(const Complex& other):real(other.real),imag(other.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& other){
22 real+=other.real;
23 imag+=other.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 if(c.imag>=0){
40 std::cout<<c.real<<"+"<<c.imag<<"i";
41 }
42 else{
43 std::cout<<c.real<<"-"<<-c.imag<<"i";
44 }
45 }
46
47 double abs(const Complex& c){
48 return std::sqrt(c.real*c.real+c.imag*c.imag);
49 }
Complex.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 }
task2.cpp
task3
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
task4
1 #ifndef FRACTION_H
2 #define FRACTION_H
3 #include<iostream>
4 #include<string>
5 class Fraction{
6 public:
7 static const std::string doc;
8 Fraction(int up,int down=1);
9 Fraction(const Fraction& other);
10 int get_up() const;
11 int get_down() const;
12 Fraction negative() const;
13 friend void output(const Fraction& f);
14 friend Fraction add(const Fraction& f1,const Fraction& f2);
15 friend Fraction sub(const Fraction& f1,const Fraction& f2);
16 friend Fraction mul(const Fraction& f1,const Fraction& f2);
17 friend Fraction div(const Fraction& f1,const Fraction& f2);
18 private:
19 int up;//分子
20 int down;//分母
21 void simplify();
22 };
23 #endif
Fraction.h
1 #include"Fraction.h"
2 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.";
3 Fraction::Fraction(int up,int down):up(up),down(down){
4 if(down==0){
5 std::cout<<"分母不能为0";
6 }
7 simplify();
8 }
9 Fraction::Fraction(const Fraction& other):up(other.up),down(other.down){}
10 int Fraction::get_up() const{
11 return up;}
12 int Fraction::get_down() const{
13 return down;}
14 Fraction Fraction::negative() const{
15 return Fraction(-up,down);
16 }
17 void Fraction::simplify() {
18 int i,m,n;
19 m=up;
20 n=down;
21 for(i=m%n;i!=0;i=m%n)
22 m=n,n=i;
23 up/=n;
24 down/=n;
25 if(down<0){
26 up*=-1;
27 down*=-1;
28 }
29 }
30 void output(const Fraction& f){
31 if(f.up==0)std::cout<<"0";
32 else if(f.down==1)std::cout<<f.up;
33 else
34 std::cout<<f.up<<"/"<<f.down;
35 }
36 Fraction add(const Fraction& f1,const Fraction& f2){
37 int new_up=f1.up*f2.down+f2.up*f1.down;
38 int new_down=f1.down*f2.down;
39 return Fraction(new_up,new_down);
40 }
41 Fraction sub(const Fraction& f1,const Fraction& f2){
42 int new_up=f1.up*f2.down-f2.up*f1.down;
43 int new_down=f1.down*f2.down;
44 return Fraction(new_up,new_down);
45 }
46 Fraction mul(const Fraction& f1,const Fraction& f2){
47 int new_up=f1.up*f2.up;
48 int new_down=f1.down*f2.down;
49 return Fraction(new_up,new_down);
50 }
51 Fraction div(const Fraction& f1,const Fraction& f2){
52 int new_up=f1.up*f2.down;
53 int new_down=f2.up*f1.down;
54 return Fraction(new_up,new_down);
55 }
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
task5
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);
17 int getId() const {return id;}
18 double getBalance()const {return balance;}
19 double getRate()const {return rate;}
20 static double getTotal() {return total;}
21 void deposit(int date, double amount);
22 void withdraw(int date, double amount);
23 void settle(int date);
24 void show() const;
25 };
26 #endif
account.h
1 #include "account.h"
2 #include <cmath>
3 #include <iostream>
4 using namespace std;
5
6 double SavingsAccount::total=0;
7 SavingsAccount::SavingsAccount(int date, int id, double rate)
8 :id(id),balance(0),rate(rate),lastDate(date),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"<<balance<<endl;
18 }
19 void SavingsAccount::deposit(int date, double amount){
20 record(date,amount);
21 }
22 void SavingsAccount::withdraw(int date, double amount) {
23 if (amount>getBalance())
24 cout<<"Error: not enough money"<<endl;
25 else
26 record(date,-amount);
27 }
28 void SavingsAccount::settle(int date) {
29 double interest=accumulate(date) * rate/365;
30 if (interest !=0)
31 record(date,interest);
32 accumulation=0;
33 }
34 void SavingsAccount::show() const {
35 cout<< "#"<<id<<"\tBalance:"<<balance;
36 }
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 sal(1, 58320212,0.015);
7 sa0.deposit(5,5000);
8 sal.deposit(25,10000);
9 sa0.deposit(45,5500);
10 sal.withdraw(60,4000);
11 sa0.settle(90);
12 sal.settle(90);
13 sa0.show(); cout<<endl;
14 sal.show(); cout<<endl;
15 cout<<"Total: "<<SavingsAccount::getTotal()<<endl;
16 return 0;
17 }
5_11.cpp
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。