任务一
t.h
#pragma once #include <string> // 类T: 声明 class T { // 对象属性、方法 public: T(int x = 0, int y = 0); // 普通构造函数 T(const T &t); // 复制构造函数 T(T &&t); // 移动构造函数 ~T(); // 析构函数 void adjust(int ratio); // 按系数成倍调整数据 void display() const; // 以(m1, m2)形式显示T类对象信息 private: int m1, m2; // 类属性、方法 public: static int get_cnt(); // 显示当前T类对象总数 public: static const std::string doc; // 类T的描述信息 static const int max_cnt; // 类T对象上限 private: static int cnt; // 当前T类对象数目 // 类T友元函数声明 friend void func(); }; // 普通函数声明 void func();
task1.cpp
#include "t.h" #include <iostream> using std::cout; using std::endl; void test(); int main() { test(); cout << "\nmain: \n"; cout << "T objects'current count: " << T::get_cnt() << endl; } void test() { cout << "test class T: \n"; cout << "T info: " << T::doc << endl; cout << "T objects'max count: " << T::max_cnt << endl; cout << "T objects'current count: " << T::get_cnt() << endl << endl; T t1; cout << "t1 = "; t1.display(); cout << endl; T t2(3, 4); cout << "t2 = "; t2.display(); cout << endl; T t3(t2); t3.adjust(2); cout << "t3 = "; t3.display(); cout << endl; T t4(std::move(t2)); cout << "t3 = "; t4.display(); cout << endl; cout << "T objects'current count: " << T::get_cnt() << endl; func(); }
t.cpp
#include "t.h" #include <iostream> #include <string> using std::cout; using std::endl; using std::string; // static成员数据类外初始化 const std::string T::doc{"a simple class sample"}; const int T::max_cnt = 999; int T::cnt = 0; // 对象方法 T::T(int x, int y): m1{x}, m2{y} { ++cnt; cout << "T constructor called.\n"; } T::T(const T &t): m1{t.m1}, m2{t.m2} { ++cnt; cout << "T copy constructor called.\n"; } T::T(T &&t): m1{t.m1}, m2{t.m2} { ++cnt; cout << "T move constructor called.\n"; } T::~T() { --cnt; cout << "T destructor called.\n"; } void T::adjust(int ratio) { m1 *= ratio; m2 *= ratio; } void T::display() const { cout << "(" << m1 << ", " << m2 << ")" ; } // 类方法 int T::get_cnt() { return cnt; } // 友元 void func() { T t5(42); t5.m2 = 2049; cout << "t5 = "; t5.display(); cout << endl; }
运行结果演示
问题1不能删除line36
原因:友元函数可以访问类的私有成员,但它依然是独立于类的函数。如果在类的实现中使用该函数,则需要为其提供普通函数的声明和定义。
报错信息:
问题2:
T(int x = 0, int y = 0);为普通构造函数。
功能: 用于初始化类的对象,可以带有默认参数。当创建对象时,如果没有提供任何参数,则使用默认值。
T(const T &t);为复制构造函数。
功能: 用于通过另一个同类对象来初始化一个新对象。用于对象的拷贝操作,例如在函数传参时传递对象,或者直接用一个对象初始化另一个对象。
T(T &&t);移动构造函数。
功能: 用于通过移动另一个同类对象来初始化一个新对象,通常用来优化性能。
调用时机:
当用一个右值对象初始化一个新对象时,例如 T obj2 = std::move(obj1);。
当返回一个对象的临时对象时,例如 T createObject() { return T(); }。
~T();析构函数。
功能: 用于清理对象所占用的资源,释放动态分配的内存。
调用时机:
当对象的生命周期结束时,即当对象超出其作用域时,如 T obj; 在函数结束时。
当对象通过 delete 被显式删除时,如 T *obj = new T(); delete obj;。
当栈上的对象超出作用域时,或者容器中的对象被移除时。
问题3
在C++11中,不能在头文件中直接初始化static成员变量。可以将其声明在头文件中,并在源文件中进行定义和初始化。
实验2
Complex.h
#ifndef COMPLEX_H #define COMPLEX_H #include <iostream> class Complex { private: double real; double imag; public: Complex(double r = 0.0, double i = 0.0); Complex(const Complex &other); double get_real() const; double get_imag() const; void add(const Complex &other) ; friend bool is_equal(const Complex &other1 , const Complex &other2); friend bool is_not_equal(const Complex &other1 , const Complex &other2); friend Complex add(const Complex &other1 , const Complex &other2); friend void output(const Complex &other); friend double abs(const Complex &other); static char doc[40]; }; bool is_equal(const Complex &other1 , const Complex &other2); bool is_not_equal(const Complex &other1 , const Complex &other2); Complex add(const Complex &other1 , const Complex &other2); void output(const Complex &other); double abs(const Complex &other); #endif
Complex.cpp
#include "Complex.h" #include <cmath> Complex::Complex(double r, double i) : real(r), imag(i) {} double Complex::get_real() const { return real; } double Complex::get_imag() const { return imag; } Complex::Complex(const Complex &other){ real = other.get_real(); imag = other.get_imag(); } void Complex::add(const Complex& other){ real += other.real; imag += other.imag; return ; } double abs(const Complex& other){ double sum; sum = other.imag * other.imag + other.real * other.real; double ave = sqrt(sum); return ave; } bool is_equal(const Complex& other1 , const Complex& other2){ if(other1.get_imag() == other2.get_imag() && other1.get_real() == other2.get_real()){ return true; } else return false; } bool is_not_equal(const Complex& other1 , const Complex& other2){ if(other1.get_imag() == other2.get_imag() && other1.get_real() == other2.get_real()){ return false; } else return true; } Complex add(const Complex& other1 , const Complex& other2){ return Complex(other1.get_real() + other2.get_real() , other1.get_imag() + other2.get_imag()); } void output(const Complex& other){ std::cout << other.get_real(); double imagy; if(other.get_imag() < 0){ std::cout << " - "; imagy = (-1.0) * other.get_imag(); } else{ std::cout << " + "; imagy = other.get_imag(); } std::cout << imagy << 'i'; return; } char Complex::doc[40] = {"a simplified Complex class"};
task2.cpp
#include "Complex.h" #include <iostream> using std::cout; using std::endl; using std::boolalpha; void test() { cout << "类成员测试: " << endl; cout << Complex::doc << endl; cout << endl; cout << "Complex对象测试: " << endl; Complex c1; Complex c2(3, -4); const Complex c3(3.5); Complex c4(c3); cout << "c1 = "; output(c1); cout << endl; cout << "c2 = "; output(c2); cout << endl; cout << "c3 = "; output(c3); cout << endl; cout << "c4 = "; output(c4); cout << endl; cout << "c4.real = " << c4.get_real() << ", c4.imag = " << c4.get_imag() << endl; cout << endl; cout << "复数运算测试: " << endl; cout << "abs(c2) = " << abs(c2) << endl; c1.add(c2); cout << "c1 += c2, c1 = "; output(c1); cout << endl; cout << boolalpha; cout << "c1 == c2 : " << is_equal(c1, c2) << endl; cout << "c1 != c3 : " << is_not_equal(c1, c3) << endl; c4 = add(c2, c3); cout << "c4 = c2 + c3, c4 = "; output(c4); cout << endl; } int main() { test(); }
任务3
#include <iostream> #include <complex> using std::cout; using std::endl; using std::boolalpha; using std::complex; void test() { cout << "标准库模板类comple测试: " << endl; complex<double> c1; complex<double> c2(3, -4); const complex<double> c3(3.5); complex<double> c4(c3); cout << "c1 = " << c1 << endl; cout << "c2 = " << c2 << endl; cout << "c3 = " << c3 << endl; cout << "c4 = " << c4 << endl; cout << "c4.real = " << c4.real() << ", c4.imag = " << c4.imag() << endl; cout << endl; cout << "复数运算测试: " << endl; cout << "abs(c2) = " << abs(c2) << endl; c1 += c2; cout << "c1 += c2, c1 = " << c1 << endl; cout << boolalpha; cout << "c1 == c2 : " << (c1 == c2) << endl; cout << "c1 != c3 : " << (c1 != c3) << endl; c4 = c2 + c3; cout << "c4 = c2 + c3, c4 = " << c4 << endl; } int main() { test(); }
任务4
function.h
#pragma once #include <string> class Fraction { public: // 类的描述信息 static const std::string doc; // 构造函数 Fraction(int up = 0, int down = 1); Fraction(const Fraction& f); // 接口函数 int get_up() const; int get_down() const; Fraction negative() const; // 友元函数声明 friend void output(const Fraction& f); friend Fraction add(const Fraction& f1, const Fraction& f2); friend Fraction sub(const Fraction& f1, const Fraction& f2); friend Fraction mul(const Fraction& f1, const Fraction& f2); friend Fraction div(const Fraction& f1, const Fraction& f2); private: int up; int down; };
function.cpp
#include "Fraction.h" #include <iostream> using std::cout; using std::endl; void test1() { cout << "Fraction类测试: " << endl; cout << Fraction::doc << endl << endl; Fraction f1(5); Fraction f2(3, -4), f3(-18, 12); Fraction f4(f3); cout << "f1 = "; output(f1); cout << endl; cout << "f2 = "; output(f2); cout << endl; cout << "f3 = "; output(f3); cout << endl; cout << "f4 = "; output(f4); cout << endl; Fraction f5(f4.negative()); cout << "f5 = "; output(f5); cout << endl; cout << "f5.get_up() = " << f5.get_up() << ", f5.get_down() = " << f5.get_down() << endl; cout << "f1 + f2 = "; output(add(f1, f2)); cout << endl; cout << "f1 - f2 = "; output(sub(f1, f2)); cout << endl; cout << "f1 * f2 = "; output(mul(f1, f2)); cout << endl; cout << "f1 / f2 = "; output(div(f1, f2)); cout << endl; cout << "f4 + f5 = "; output(add(f4, f5)); cout << endl; } void test2() { Fraction f6(42, 55), f7(0, 3); cout << "f6 = "; output(f6); cout << endl; cout << "f7 = "; output(f7); cout << endl; cout << "f6 / f7 = "; output(div(f6, f7)); cout << endl; } int main() { cout << "测试1: Fraction类基础功能测试\n"; test1(); cout << "\n测试2: 分母为0测试: \n"; test2(); return 0; }
任务5
account.h
#include<iostream> class SavingsAccount{ private: int id; double balance; double rate; int lastDate; double accumulation; static double total; void record(int date,double amount); double accumulate(int date) const{ return accumulation+balance*(date-lastDate); } public: SavingsAccount(int date,int id,double rate); int getId() const {return id;} double getBalance() const{return balance;} double getRate() const{return rate;} static double getTotal(){return total;} void deposit(int rate,double amount); void withdraw(int rate,double amount); void settle(int date); void show() const; };
account.cpp
#include "account.h" #include<cmath> #include<iostream> using std::cout; using std::endl; double SavingsAccount::total=0; SavingsAccount::SavingsAccount(int date,int id,double rate) :id(id),balance{0},rate{rate},lastDate{date},accumulation{0}{ cout<<date<<"\t#"<<id<<"is created"<<endl; } void SavingsAccount::record(int date,double amount){ accumulation=accumulate(date); lastDate=date; amount=floor(amount*100+0.5)/100; balance+=amount; total+=amount; cout<<date<<"\t#"<<id<<"\t"<<amount<<"\t"<<balance<<endl; } void SavingsAccount::deposit(int date,double amount){ record(date,amount); } void SavingsAccount::withdraw(int date,double amount){ if(amount>getBalance()){ cout<<"Erroe:not enough money"<<endl; } else{ record(date,-amount); } } void SavingsAccount::settle(int date){ double interest=accumulate(date)*rate/365; if(interest!=0){ record(date,interest); } accumulation=0; } void SavingsAccount::show() const{ cout<<"#"<<id<<"\tBalance:"<<balance; }
task5
#include "account.h" #include<iostream> using namespace std; int main(){ SavingsAccount sa0(1,21325302,0.015); SavingsAccount sa1(1,58320212,0.015); sa0.deposit(5,5000); sa1.deposit(25,10000); sa0.deposit(45,5500); sa1.withdraw(60,4000); sa0.settle(90); sa1.settle(90); sa0.show();cout<<endl; sa1.show();cout<<endl; cout<<"Total:"<<SavingsAccount::getTotal()<<endl; return 0; }
标签:std,const,int,double,Complex,实验,include From: https://www.cnblogs.com/Jjjzz1/p/18514735