实验任务1
代码：
t.h:
1 #pragma once
2
3 #include<string>
4
5 class T {
6 public:
7 T(int x = 0, int y = 0);
8 T(const T& t);
9 T(T&& t);
10 ~T();
11 void adjust(int ratio);
12 void display()const;
13 private:
14 int m1, m2;
15
16 public:
17 static int get_cnt();
18
19 public:
20 static const std::string doc;
21 static const int max_cnt;
22
23 private:
24 static int cnt;
25
26 friend void func();
27 };
28
29 void func();
t.cpp:
1 #include"t.h"
2 #include<iostream>
3 #include<string>
4
5 using std::cout;
6 using std::endl;
7 using std::string;
8
9 const std::string T::doc{ "a simple class sample" };
10 const int T::max_cnt = 999;
11 int T::cnt = 0;
12
13 T::T(int x, int y) :m1{ x }, m2{ y } {
14 ++cnt;
15 cout << "T constructor called.\n";
16 }
17
18 T::T(const T& t) :m1{ t.m1 }, m2{ t.m2 } {
19 ++cnt;
20 cout << "T copy constructor called.\n";
21 }
22
23 T::T(T&& t) :m1{ t.m1 }, m2{ t.m2 } {
24 ++cnt;
25 cout << "T move constructor called.\n";
26 }
27
28 T::~T() {
29 --cnt;
30 cout << "T destructor called.\n";
31 }
32
33 void T::adjust(int ratio) {
34 m1 *= ratio;
35 m2 *= ratio;
36 }
37
38 void T::display()const {
39 cout << "(" << m1 << "," << m2 << ")";
40 }
41
42 int T::get_cnt() {
43 return cnt;
44 }
45
46 void func() {
47 T t5(42);
48 t5.m2 = 2049;
49 cout << "t5="; t5.display(); cout << endl;
50 }
task.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;
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 objects'current count:" << T::get_cnt() << endl;
35
36 func();
37 }
运行截图：
问题1：
不能去掉，因为func在类内声明了友元函数，但没有声明为普通函数，删掉会显示找不到此函数。
问题2：line9是普通构造函数，给定了两个默认的参数初始值。在系统定义类的对象时，如果定义形式是T t(括号内可以有0到两个参数)，就调用该函数。
line10是复制构造函数，将t指向调用时输入的对象，但不改变其的值。
line11是移动构造函数，通过移动而不复制实参的方式提高运行效率。
line12是析构函数，之前的各类构造函数调用完成后，调用该函数，释放他们的空间。一般在主函数结束后调用。
问题3：不能
实验任务2
代码：
complex.h:
1 #pragma once
2 #include<string>
3 class Complex {
4 public:
5 static std::string doc;
6 Complex(double x1 = 0, double y1 = 0);
7 Complex(const Complex& c);
8 ~Complex() {}
9 double get_real() ;
10 double get_imag() ;
11 void add(const Complex &d) ;
12 friend Complex add(const Complex &e, const Complex &f);
13 friend bool is_equal(const Complex &e,const Complex &f);
14 friend bool is_not_equal(const Complex &e,const Complex &f);
15 friend void output(const Complex& e);
16 friend double abs(const Complex &g);
17
18 private:
19 double x, y;
20 };
21
22 bool is_equal(const Complex &e,const Complex&f);
23 bool is_not_equal(const Complex &e,const Complex&f);
24 void output(const Complex& e);
complex.cpp:
1 #include"complex.h"
2 #include<iostream>
3 #include<string>
4 Complex::Complex(double x1, double y1):x{ x1 }, y{ y1 } {}
5
6 Complex::Complex(const Complex& c) :x{ c.x }, y{ c.y } {}
7 double Complex::get_real() {
8 return x;
9 }
10 double Complex::get_imag() {
11 return y;
12 }
13 void Complex::add(const Complex& d) {
14 x += d.x;
15 y += d.y;
16 }
17 Complex add(const Complex& e,const Complex& f) {
18 Complex h;
19 h.x = e.x + f.x;
20 h.y = e.y + f.y;
21 return h;
22 }
23 bool is_equal(const Complex &e,const Complex &f) {
24 return e.x == f.x && e.y == f.y;
25 }
26 bool is_not_equal(const Complex& e, const Complex& f) {
27 return e.x != f.x || e.y != f.y;
28 }
29
30 void output(const Complex& e) {
31 std::cout << e.x << e.y << "i";
32 }
33 double abs(const Complex& g) {
34 return sqrt(g.x * g.x + g.y * g.y);
35 }
36 std::string Complex::doc = "a simplified complex class";
task2.cpp:
1 #include <iostream>
2 #include"complex.h"
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 }
运行截图：
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 }
运行截图：
实验任务4
代码：
Fraction.h:
1 #pragma once
2 #include<string>
3
4 class Fraction {
5 public:
6 static const std::string doc;
7 Fraction(int x=1, int y = 1);
8 Fraction(const Fraction& p);
9 int get_up();
10 int get_down();
11 Fraction negative();
12
13 public:
14 friend void output(Fraction p);
15 friend Fraction add(const Fraction& a, const Fraction& b);
16 friend Fraction sub(const Fraction& a, const Fraction& b);
17 friend Fraction mul(const Fraction& a, const Fraction& b);
18 friend Fraction div(const Fraction& a, const Fraction& b);
19
20 private:
21 int up, down;
22
23 };
24
25 void output( Fraction p);
26
27
28 int computeGCD(int a, int b);
Fraction.cpp:
1 #include"Fraction.h"
2 #include<iostream>
3 #include<string>
4
5 const std::string Fraction::doc = "Fraction类v0.01版.\n目前仅支持分数对象的构造、输出、加/减/乘/除运算.";
6
7 Fraction::Fraction(int x,int y):up{x},down{y}{}
8 Fraction::Fraction(const Fraction &p):up{p.up},down{p.down}{}
9 int Fraction::get_up(){
10 int gcd = computeGCD(up, down);
11 up /= gcd;
12 down /= gcd;
13 return up;
14 }
15 int Fraction::get_down(){
16 int gcd = computeGCD(up,down);
17 up /= gcd;
18 down /= gcd;
19 return down;
20 }
21 Fraction Fraction::negative() {
22 return Fraction(-up, down);
23 }
24 void output(Fraction p) {
25 int gcd = computeGCD(p.up, p.down);
26 p.up /= gcd;
27 p.down /= gcd;
28 if (p.down == 1) {
29 std::cout << p.up;
30 }
31 else if ( p.down > 0&&p.down!=1) {
32 std::cout << p.up << "/" << p.down;
33 }
34 else if (p.down == 0) {
35 std::cout << "分母不能为0";
36 }
37 else std::cout << -p.up << "/" << -p.down;
38 }
39 Fraction add(const Fraction& a, const Fraction& b) {
40 Fraction c;
41 c.up = a.up*b.down+ b.up*a.down;
42 c.down = a.down * b.down;
43 return c;
44 }
45 Fraction sub(const Fraction& a, const Fraction& b) {
46 Fraction c;
47 c.down = a.down * b.down;
48 c.up = a.up * b.down - a.down * b.up;
49 int gcd = computeGCD(c.up, c.down);
50 c.up /= gcd;
51 c.down /= gcd;
52 return c;
53 }
54 Fraction mul(const Fraction& a, const Fraction& b) {
55 Fraction c;
56 c.down = a.down * b.down;
57 c.up = a.up * b.up;
58 int gcd = computeGCD(c.up, c.down);
59 c.up /= gcd;
60 c.down /= gcd;
61 return c;
62 }
63 Fraction div(const Fraction& a, const Fraction& b) {
64 Fraction c;
65 if (b.up != 0 && b.down != 0) {
66 c.down = a.down * b.up;
67 c.up = a.up * b.down;
68 int gcd = computeGCD(c.up, c.down);
69 c.up /= gcd;
70 c.down /= gcd;
71 return c;
72 }
73 else {
74 return Fraction(1, 0);
75 }
76 }
77
78 int computeGCD(int a, int b) {
79 while (b != 0) {
80 int temp = b;
81 b = a % b;
82 a = temp;
83 }
84 return a < 0 ? -a : a;
85 }
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 }
运行截图：
实验任务5
代码：
account.h:
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 public:
18 SavingsAccount(int date, int id, double rate);
19 int getId()const { return id; }
20 double getBanlance()const { return balance; }
21 double getRate()const { return rate; }
22 static double getTotal() { return total; }
23 void deposit(int date, double amcount);
24 void withdraw(int date, double amount);
25 void settle(int date);
26 void show()const;
27 };
28 #endif
account.cpp:
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 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 > getBanlance())
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 }
5_11.cpp:
1 #include"account.h"
2 #include<iostream>
3 using namespace std;
4 int main() {
5 SavingsAccount sa0(1, 21325302, 0.0015);
6 SavingsAccount sa1(1, 58320212, 0.0015);
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 }
运行截图：
实验总结：在类的定义中有许多小细节，要十分注意，不然报错一大堆就会很头疼。
标签：const,对象,double,编程,int,Complex,实验,Fraction,include From： https://www.cnblogs.com/sqmylc/p/18493603