第10
下面是不完整的类定义：
class A {
public：
virtual void print（）{
cout << “print come form class A” << endl;
}
};
B类：公共A{
私人：
字符*buf;
public：
void print（） {
cout << “print come from class B” << endl;
}
};
void fun（A *a） {
delete a;
}
试完成其定义（需要增加必要的构造函数、析构函数）。
类A析构函数输出：A：：~A（）类B析构函数输出：B：：~B（）给定如下main函数：
int main（） {
A *a = new B（10）;
a->print（）;
fun（a）;
B *b = 新 B（20）;
乐趣（b）;
返回 0;
}
【输入】
没有输入。
【输出】
主函数的输出已经写好。
/* 请在此处分别编写A、B类 */
class A
{
public:virtual void print() {cout << "print come form class A" << endl;}virtual ~A(){cout << "A::~A() called" << '\n';}
};class B : public A {
private:char* buf;
public:B(int x){}void print() {cout << "print come from class B" << endl;}~B(){cout << "B::~B() called" << '\n';}
};（1）声明并实现一个名为Arc的类，在二维空间中以某一个点为中心，绘制圆弧。Arc类包含私有数据成员p（圆心，Point类型），radius（圆弧半径，double类型）;有参构造函数，将圆心、圆弧半径设置为给定的参数;成员函数draw，输出圆心和半径。
（2）声明并实现一个名为Circle的类，在二维空间中以某一个点为中心，绘制圆。Circle类包含私有数据成员p（圆心，Point类型），radius（圆半径，double类型）;有参构造函数，将圆心、圆半径设置为给定的参数;成员函数draw，输出圆心和半径。【输入】
没有输入。
【输出】
【提示】
需要自定义Point类。
给定如下main函数：
int main（） {
Point p（320， 240）;
混合混合（p， 100， 70）;
mix.draw（）;
返回 0;/* 请在此处分别编写Point、Arc、Circle、Ellipse、Rectangle、Mix类 */
class Point
{
public:int x, y;
public:Point(){}Point(int x, int y){this->x = x;this->y = y;}
};class Arc
{
private:Point p;double radius;
public:Arc(Point p, double radius){this->p = p;this->radius = radius;}void draw(){cout << "Drawing an arc: Center(" << p.x << ", " << p.y << ")" << ",radius(" << radius << ")" << '\n';}
};class Circle
{
private:Point p;double radius;
public:Circle(Point p, double radius){this->p = p;this->radius = radius;}void draw(){cout << "Drawing an circle: Center(" << p.x << ", " << p.y << "),radius(" << radius << ")" << '\n';}
};class Ellipse
{
private:Point p;double xRadius, yRadius;
public:Ellipse(Point p, double xRadius, double yRadius){this->p = p;this->xRadius = xRadius;this->yRadius = yRadius;}void draw(){cout << "Drawing an ellipse: Center(" << p.x << ", " << p.y << "),x-axis(" << xRadius << "),y-axis(" << yRadius << ")" << '\n';}
};class Rectangle
{
private:Point p;double width, height;
public:Rectangle(Point p, double width, double height){this->p = p;this->width = width;this->height = height;}void draw(){cout << "Drawing an rectangle: Upper left corner coordinates("<< p.x << ", " << p.y << ")width(" << width<< "), height(" << height << ")" << '\n';}
};class Mix : public Arc, public Circle, public Ellipse, public Rectangle
{
public:Mix(Point p, int a, int b):Arc(p, a), Circle(p, b), Ellipse(p, a, b), Rectangle(p, a, b){}void draw(){Arc::draw();Circle::draw();Ellipse::draw();Rectangle::draw();}
};（ 1 ）声明并实现一个名为 Person 的基类， Person 类有保护数据成员 name （姓名， string 类型）、（性别， char 类型， ' M ' 表示男， ' F ' 表示女）。以及有参构造函数，将姓名、性别设置为给定的参数;成员函数print，输出姓名和性别。
（2）从Person类派生出Student类，Student类有私有数据成员status（状态，枚举类型），表示年级（FRESHMAN、SOPHOMORE、JUNIOR、SENIOR），表示大一、大二、大三、大四学生。以及有参构造函数，将姓名、性别、状态设置为给定的参数;成员函数print，print函数输出姓名、性别和状态。
【输入】
没有输入。
【输出】
<span style="color:#000000">Name:ZhangSan, Sex:M
Name:LiSi, Sex:F</span>/* 请在此处分别编写Person、Student、MyDate、Employee、Faculty、Staff类 */
class Person {
protected:string name;char sex;public:Person() {}Person(string name, char sex){this->name = name;this->sex = sex;}void print(){cout << "Name:" << name << ", Sex:" << sex << endl;}
};enum Status { FRESHMAN, SOPHOMORE, JUNIOR, SENIOR };class Student : public Person {
private:Status status;public:Student() {}Student(string name, char sex, Status status){this->name = name;this->sex = sex;this->status = status;}void print(){cout << "Name:" << name << ", Sex:" << sex << endl;cout << "Status:" << (status == 0 ? "Freshman" : status == 1 ? "Sophomore" : status == 2 ? "Junior" : "Senior") << endl;}
};class MyDate {
private:int year, month, day;public:MyDate(int year = 1900, int month = 1, int day = 1){this->year = year;this->month = month;this->day = day;}void print(){cout << year << "-" << month << "-" << day << endl;}
};class Employee : public Person {
protected:int salary;MyDate dateHired;public:Employee() {}Employee(string name, char sex, int salary, MyDate dateHired){this->name = name;this->sex = sex;this->salary = salary;this->dateHired = dateHired;}void print(){cout << "Name:" << name << ", Sex:" << sex << endl;cout << "Salary:" << salary << ", Hire date:";dateHired.print();}
};enum Rank { PROFESSOR, ASSOCIATE_PROFESSOR, LECTURER };class Faculty : public Employee {
private:Rank rank;public:Faculty() {}Faculty(string name, char sex, int salary, MyDate dateHired, Rank rank){this->name = name;this->sex = sex;this->salary = salary;this->dateHired = dateHired;this->rank = rank;}void print(){cout << "Name:" << name << ", Sex:" << sex << endl;cout << "Salary:" << salary << ", Hire date:";dateHired.print();cout << "Rank:" << (rank == 0 ? "Professor" : rank == 1 ? "Associate_Professor" : "Lecturer") << endl;}
};enum Headship { PRESIDENT, DEAN, DEPARTMENT_CHAIRMAN };class Staff : public Employee {
private:Headship headship;public:Staff() {}Staff(string name, char sex, int salary, MyDate dateHired, Headship headship){this->name = name;this->sex = sex;this->salary = salary;this->dateHired = dateHired;this->headship = headship;}void print(){cout << "Name:" << name << ", Sex:" << sex << endl;cout << "Salary:" << salary << ", Hire date:";dateHired.print();cout << "Headship:" << (headship == 0 ? "President" : headship == 1 ? "Dean" : "Department_Chairman" ) << endl;}
};（1）员工类是抽象类。Employee类的派生类有Boss类、CommissionWorker类、PieceWorker类和HourlyWorker类。
（2）Employee类包括私有数据成员name（姓名，string类型）;有参构造函数，将name设置为给定的参数;访问器函数getName;还有纯虚函数show和earnings。show和earning函数将在每个派生类中实现，因为每个派生类显示的信息不同、计算工资的方法不同。
【输入】
输入Boss的姓名和周工资。
输入CommissonWorker的姓名、工资、佣金和销售数量。
输入PieceWorker的姓名、每件产品工资和生产数量。
输入HourlyWorker的姓名、小时工资、工作时数。
【输出】
见【输出示例】
【输入示例】
<span style="color:#000000">ZhangSan 800.0
LiSi 400.0 3.0 150
WangWu 2.5 200
LiuLiu 13.75 40</span>class Employee {
private:string name;public:Employee() {}Employee(string name){this->name = name;}string getName(){return name;}virtual void show() {}virtual double earnings(){return 1.0;}
};class Boss : public Employee {
private:double weeklySalary;public:Boss() {}Boss(string name, double weeklySalary) : Employee(name){this->weeklySalary = weeklySalary;}void setWeeklySalary(double weeklySalary){this->weeklySalary = weeklySalary;}void show(){cout << "Boss: " << getName() << endl;}double earnings(){return weeklySalary;}
};class CommissionWorker : public Employee {
private:double salary;double commission;int quantity;public:CommissionWorker() {}CommissionWorker(string name, double salary, double commission, int quantity) : Employee(name){this->salary = salary;this->commission = commission;this->quantity = quantity;}void setSalary(double salary){this->salary = salary;}void setCommision(double commision){this->commission = commision;}void setQuantity(int quantity){this->quantity = quantity;}void show(){cout << "Commision Worker: " << getName() << endl;}double earnings(){return salary + commission * quantity;}
};class PieceWorker : public Employee {
private:double wagePerPiece;int quantity;public:PieceWorker() {}PieceWorker(string name, double wagePerPiece, int quantity) : Employee(name){this->wagePerPiece = wagePerPiece;this->quantity = quantity;}void setWage(){this->wagePerPiece = wagePerPiece;}void setQuantity(){this->quantity = quantity;}void show(){cout << "Piece Worker: " << getName() << endl;}double earnings(){return wagePerPiece * quantity;}
};class HourlyWorker : public Employee {
private:double wage;double hours;public:HourlyWorker() {}HourlyWorker(string name, double wage, double hours) : Employee(name){this->wage = wage;this->hours = hours;}void setWage(){this->wage = wage;}void setHours(){this->hours = hours;}void show(){cout << "Hourly Worker: " << getName() << endl;}double earnings(){return wage * hours;}
}; （1）声明并实现一个名为Vehicle的基类，表示汽车。Vehicle类包括：
int类型的私有数据成员numberOfDoors，表示车门数量。
int类型的私有数据成员数OfCylinders，表示气缸数量。
string类型的私有数据成员color，表示汽车颜色。
double类型的私有数据成员fuelLevel，表示油位，即燃油数量。
int类型的私有数据成员transmissionType，表示变速箱类型，即0表示手动、1表示自动。
string类型的私有数据成员className，表示汽车类别。
【输入】
输入车门数量、气缸数量，颜色、燃油数量、变速箱类型。
【输出】
见【输出示例】
【输入示例】
2 6 red 50 1 4 6 yellow 60 0 2 16 black 100 0
/* 请在此处分别编写Vehicle、Taxi和Truck类 */
/* 请在此处分别编写Vehicle*/
class Vehicle
{
private:int numberOfDoors, numberOfCylinders, transmissionType;string color, className;double fuelLevel;
public:Vehicle(){}Vehicle(int numberOfDoors, int numberOfCylinders, string color,double fuelLevel, int transmissionType){this->color = color;this->fuelLevel = fuelLevel;this->numberOfCylinders = numberOfCylinders;this->numberOfDoors = numberOfDoors;this->transmissionType = transmissionType;}int getNumberOfDoors(){return numberOfDoors;}int getNumberOfCylinders(){return numberOfCylinders;}int getTransmissionType(){return transmissionType;}string getColor(){return color;}string getClassName(){return className;}double getFuelLevel(){return fuelLevel;}void setColor(string color){this->color = color;}void setClassName(string className){this->className = className;}void setFuelLevel(double fuelLevel){this->fuelLevel = fuelLevel;}friend ostream& operator << (ostream& out, const Vehicle& a){out << "Vehicle" << '\n'<< "Number of doors:" << a.numberOfDoors << '\n'<< "Number of cylinders:" << a.numberOfCylinders << '\n'<< "Transmission type:";if (a.transmissionType)out << "Automatic";elseout << "Manual";out << '\n'<< "Color:" << a.color << '\n'<< "Fuel level:" << a.fuelLevel << '\n';return out;}
};class Taxi : public Vehicle
{
private:bool customers;int numberOfDoors, numberOfCylinders, transmissionType;string color, className;double fuelLevel;
public:Taxi(int numberOfDoors, int numberOfCylinders, string color,double fuelLevel, int transmissionType, bool customers){this->color = color;this->fuelLevel = fuelLevel;this->numberOfCylinders = numberOfCylinders;this->numberOfDoors = numberOfDoors;this->transmissionType = transmissionType;this->customers = customers;}bool hasCustomers(){return customers;}void setCustomers(bool customers){this->customers = customers;}friend ostream& operator << (ostream& out, const Taxi& a){out << "Vehicle" << '\n'<< "Number of doors:" << a.numberOfDoors << '\n'<< "Number of cylinders:" << a.numberOfCylinders << '\n'<< "Transmission type:";if (a.transmissionType)out << "Automatic";elseout << "Manual";out << '\n'<< "Color:" << a.color << '\n'<< "Fuel level:" << a.fuelLevel << '\n';if (a.customers)out << "Has passengers" << '\n';elseout << "Has no passengers" << '\n';return out;}
};class Truck : public Vehicle
{
private:bool cargo;int numberOfDoors, numberOfCylinders, transmissionType;string color, className;double fuelLevel;
public:Truck(int numberOfDoors, int numberOfCylinders, string color,double fuelLevel, int transmissionType, bool cargo){this->color = color;this->fuelLevel = fuelLevel;this->numberOfCylinders = numberOfCylinders;this->numberOfDoors = numberOfDoors;this->transmissionType = transmissionType;this->cargo = cargo;}bool hasCargo(){return cargo;}void setCargo(bool cargo){this->cargo = cargo;}friend ostream& operator << (ostream& out, const Truck& a){out << "Vehicle" << '\n'<< "Number of doors:" << a.numberOfDoors << '\n'<< "Number of cylinders:" << a.numberOfCylinders << '\n'<< "Transmission type:";if (a.transmissionType)out << "Automatic";elseout << "Manual";out << '\n'<< "Color:" << a.color << '\n'<< "Fuel level:" << a.fuelLevel << '\n';if (a.cargo)out << "Has passengers" << '\n';elseout << "Has no passengers" << '\n';return out;}
};下面是类A的定义，需要补充或增加完整的无参构造函数、虚析构函数以及fun（）虚函数。
A 类 {
公共：
// ...
void g（） {
fun（）;
}
};
构造函数输出：A constructor，并调用g（）函数
析构函数输出：A destructor
fun（）函数输出：Call class A's fun
下面是类B的定义，继承类A，需要补充或增加完整的无参构造函数、析构函数。
B类 {
公共：
// ...
};
无参构造函数输出：B constructor
析构函数输出：B destructor/* 请在此处编写A、B、C类 */
class A
{
public:A(){cout << "A constructor" << '\n';g();}virtual ~A(){cout << "A destructor" << '\n';}virtual void fun(){cout << "Call class A's fun" << '\n';}void g(){fun();}
};class B : public A
{
public:B(){cout << "B constructor" << '\n';}virtual ~B(){cout << "B destructor" << '\n';}
};class C : public B
{
public:C(){cout << "C constructor" << '\n';}virtual~C(){cout << "C destructor" << '\n';}virtual void fun(){cout << "Call class C's fun" << '\n';}
};
按要求计算数值。
【输入】
第一行是整数n，表示第二行有n个整数。
第二行：n个整数。
所有整数都在0和100之间。
【输出】
先输出：
1
100
101
101
对于输入中第二行的每个整数x，输出两行：
第一行：k=x;
第二行：x的平方。
【输入示例】/* 请在此处编写相关代码 */
/* 请在此处编写相关代码 */
A(int x){n = x;}A operator ++ (int){A temp = *this;n++;return temp;}A& operator ++ (){n++;return *this;}friend ostream& operator<<(ostream& output,const A& a){output << a.n;return output;}operator int() const{return n;}有5个类A、B、C、D、E。它们的形式均为：
class T {
public：
T（） {
cout << “T（）” << endl;
}
~T（） {
cout << “~T（）” << endl;
}
};
这里T代表类名A、B、C、D、E。
给定如下main函数：
int main（） {
E e;
return 0;
}/* 请在此处分别编写A、B、C、D、E类，注意：类A、B、C、D、E之间的继承关系 */
/* 请在此处分别编写A、B、C、D、E类，注意：类A、B、C、D、E之间的继承关系 */
class C {
public:C() {cout << "C()" << endl;}~C() {cout << "~C()" << endl;}
};class B : public C{
public:B() {cout << "B()" << endl;}~B() {cout << "~B()" << endl;}
};class A : public C {
public:A() {cout << "A()" << endl;}~A() {cout << "~A()" << endl;}
};class D : public A {
public:D() {cout << "D()" << endl;}~D() {cout << "~D()" << endl;}
};class E : public B, public D {
public:E() {cout << "E()" << endl;}~E() {cout << "~E()" << endl;}
};将输入数据按特定要求原样输出。
【输入】
第一行是整数t，表明一共t组数据。
对每组数据：
第一行是整数n，表示下面一共有n行，0<n<100。
下面的每行，以一个字母开头，然后跟着一个整数，两者用空格分隔。字母只会是'A'或'B'。整数范围0到100。
【输出】
对每组输入数据，将其原样输出，每组数据的最后输出一行“****”。
【输入示例】
【输出示例】/* 请在此处编写A、B类和PrintInfo函数，并定义a数组 */
/* 请在此处编写A、B类和PrintInfo函数，并定义a数组 */
class A
{
public:int x;char op;
public:A() {};A(int x){this->x = x;op = 'A';}//~A() {}
};class B : public A
{
public:B(int x){this->x = x;op = 'B';}//~B() {};
};A * a[1000];void PrintInfo(A* a)
{cout << a->op << ' ' << a->x << '\n';
}（1）Shape类是抽象类，包括了纯虚函数getArea（求面积）、getPerimeter（求周长）、show（输出对象信息）以及成员函数getClassName（返回类名“Shape”）。
（2）Circle类继承了Shape类，包括了double类型的私有数据成员radius，表示圆半径;带默认参数的有参构造函数，radius的默认参数值为1;访问器函数getRadius和更改器函数setRadius;重定义了getArea（求圆面积）【输入示例】
3.5
5.8 11.8
1 1.5 1/* 请在此处编写Shape、Circle、Rectangle和Triangle类 */
class Shape
{
public:virtual double getArea() { return 0; }virtual double getPerimeter() { return 0; }virtual void show() {}virtual string getClassName() { return ""; }
};class Circle : public Shape
{
private:double radius;
public:Circle(double r = 1){radius = r;}double getRadius(){return radius;}void setRadius(double r){radius = r;}double getArea() {return PI * radius * radius;}double getPerimeter(){return PI * radius * 2;}void show() {cout << "Radius:" << radius << '\n';}string getClassName() {return "Circle";}
};class Rectangle : public Shape
{
private:double width, height;
public:Rectangle(double w = 1, double h = 1){width = w;height = h;}double getWidth(){return width;}void setWidth(double w){width = w;}double getHeight(){return height;}void setHeight(double r){height = r;}double getArea(){return width * height;}double getPerimeter(){return (width + height) * 2;}void show(){cout << "Width:" << width << ", Height：" << height << '\n';}string getClassName(){return "Rectangle";}
};class Triangle : public Shape
{
private:double side1, side2, side3;
public:Triangle(double a, double b, double c){side1 = a;side2 = b;side3 = c;}double getArea(){double p = (side1 + side2 + side3) / 2;return sqrt(p * (side1 - p) * (side2 - p)* (side3 - p));}double getPerimeter(){return side1 + side2 + side3;}void show(){cout << "Side:" << side1 << ", " << side2 << ", " << side3 << '\n';}string getClassName(){return "Triangle";}
};十一
声明并实现一个Student类，表示学生信息。Student类包括：
int类型的私有数据成员num，表示学号。
string类型的私有数据成员name，表示姓名。
int类型的私有数据成员score，表示成绩
char类型的私有数据成员grade，表示等级。
无参（默认）构造函数。
【输入】
输入若干个学生的信息。
每行一个学生信息，学号、姓名和成绩之间以空格间隔。
学号为0时，输入结束。
【输出】
文件学生.txt。
不需要在屏幕上显示信息。
#include <iostream>
#include <fstream>
#include <string>
#include <cstdlib>
using namespace std;
class Student {
public:Student(int num, string name, int score, char grade) {this->num = num;this->name = name;this->score = score;this->grade = grade;}int getNum() const {return num;}string getName() const {return name;}int getScore() const {return score;}char getGrade() const {return grade;}friend ostream &operator<<(ostream &out, const Student &student);friend istream &operator>>(istream &in, Student &student);
private:int num; string name;int score; char grade;
};
ostream &operator<<(ostream &out, const Student &student) {out << student.num << " " << student.name << " "<< student.score << " " << student.grade << endl;return out;
}
istream &operator>>(istream &in, Student &student) {in >> student.num >> student.name >> student.score >> student.grade;return in;
}
int main() {ofstream outFile;outFile.open("student.txt");if(!outFile.is_open()) {exit(EXIT_FAILURE);}int num;string name;int score;char grade;cin >> num;while(num != 0) {cin >> name >> score;switch(score / 10) {case 10:case 9: grade = 'A';break;case 8: grade = 'B';break;case 7: grade = 'C';break;case 6: grade = 'D';break;default: grade = 'E';break;}Student student(num, name, score, grade);outFile << student;cin >> num;}outFile.close();return 0;
}以二进制方式打开图片文件并读取该文件中的第 13（从1开始计数，后同）,49, 80 个字节处的值，求这3个二进制数按位异或的结果（16进制表示）。
可以鼠标右键另存为下载图片文件：
#include <iostream>
#include <fstream>
using namespace std;
int main() {ifstream fin("image.jpg", ios::binary);char byte1, byte2, byte3;fin.seekg(12, ios::beg);fin.read((char *)&byte1, 1);fin.seekg(48, ios::beg);fin.read((char *)&byte2, 1);fin.seekg(79, ios::beg);fin.read((char *)&byte3, 1);cout << hex << ((byte1 ^ byte2 ^ byte3) & 0x000000ff) << endl;return 0;
}将一个明文文件plaintext.txt中的内容，按照一定的方法，对每个字符加密后存放到另一个密文文件ciphertext.txt中。
【输入】
文件.txt。（该文件已经存在，无需自己创建）
注意：本地调试程序时，则要求自己预先建立好plaintext.txt文件。在Windows下，可以使用记事本。
#include<iostream>
#include<string>
#include<fstream>
using namespace std;
int main(){ifstream ifs;ofstream ofs;ifs.open("plaintext.txt");ofs.open("ciphertext.txt");string buf;while (getline(ifs, buf)) {for (int i = 0; i < buf.length(); i++) {ofs << char(buf[i] + 2);}ofs<< '\n';} ifs.close();ofs.close();return 0;
}【描述】
输入一篇英文文章，求出现次数前三名的字母，不区分大小写（即出现A也计入出现a的次数中），按照次数由大到小输出，如果出现次数一样，按字典顺序输出。其它字符不予考虑。
附带说明：英文中，每个字母出现的频率是不一样的，在破译英文密码时，尤其是凯撒密码，统计每个字母出现的频率有着重要意义。
可以下载英文文章：
#include<bits/stdc++.h>
#include<unordered_map>
#define ll long long
#define ull unsigned long long
#define IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
struct node {char ch;ll cnt;bool operator < (const node& b) const{return cnt > b.cnt;}
}a[26];int main()
{fstream f;f.open("news.txt");string s;for (ll i = 0; i <= 25; i++)a[i].ch = 'a' + i;while (getline(f, s)){for (char i : s){if (!isalpha(i))continue;if (i <= 'Z')a[i + 32 - 'a'].cnt++;elsea[i - 'a'].cnt++;}}sort(a, a + 26); for (ll i = 0; i <= 2; i++)cout << a[i].ch << ":" << a[i].cnt << '\n';return 0;
}处理日志文件，日志文件的储存格式为“年/月/日 时：分：秒 用户名 操作”。
日志文件有多条记录：
2015/4/218：00：33 37c3b6b58c6ac3 LOGIN
2015/4/218：15：35 11734e186f24fe4c LOGIN
2015/4/218：34：57 9f3cf331d19a9f LOGIN
2015/4/219：00：29 389bcca2159f5de7 LOGIN
2015/4/219：08：29 c3bde693fdb3c3d LOGIN
文件times.txt，注意：这里只给出了其中部分内容。
37c3b6b58c6ac 31887052
11734e186f24fe4c 2088931
9f3cf331d19a9f 2147511
389bcca2159f5de 71398643
c3bde693fdb3c3d 1297166
#include<bitsdc++.h>
using namespace std;
typedef long long ll;const ll daytime = 86400;
int pos;struct node{string id;ll sum,last;
} a[10100];ll work(string date, string time) {ll ans = 0, day, hour, min, sec,month;month = date[5] - '0';if (date.size() == 9) {day = (date[7] - '0') * 10 + date[8] - '0';} else {day = date[7] - '0';}if (month == 4) {ans += (day - 21) * daytime;} else if (month == 5) {ans += daytime * (9 + day );} else {ans += daytime * (40 + day);}if (time.size() == 7) {hour = time[0] - '0';min = (time[2] - '0') * 10 + time[3] - '0';sec = (time[5] - '0') * 10 + time[6] - '0';} else {hour = (time[0] - '0') * 10 + time[1] - '0';min = (time[3] - '0') * 10 + time[4] - '0';sec = (time[6] - '0') * 10 + time[7] - '0';}ans += hour * 3600 + min * 60 + sec;return ans;
}int add(string name) {for (int i = 1; i <= pos; i++) {if (name== a[i].id){return i;}}a[++pos]={name,0,0};return pos;
}int main() {ifstream inFile;inFile.open("log.txt");ofstream outFile;outFile.open("times.txt");string date, time, name, op;pos = 0;while (inFile>> date>> time>> name>> op) {//cout<<" "<<date<<" "<<time<<" "<<name<<" "<<op<<endl;int x = add(name);int tmp = work(date, time);if (op== "LOGIN") {a[x].last = tmp;} else {a[x].sum += tmp - a[x].last;}}for (int i = 1; i <= pos; ++i) {outFile<< a[i].id<<" "<<a[i].sum<<endl;//cout<< a[i].id<<" "<<a[i].sum<<endl;;}return 0;
}
【描述】
输入10个整数存入文本文件example.txt中，文件每行存放5个整数，每行整数之间用一个空格间隔。行末不能有多余的空格。
【输入】
输入10个整数。
【输出】
生成文件示例.txt，里面存放输入的10个整数。
不需要在屏幕上显示整数。
【输入示例】
1 2 3 4 5 6 7 8 9 10
【输出示例】
生成文件example.txt，其中内容：
1 2 3 4
6 7 8 9 10
#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;
int main() {ofstream outFile;outFile.open("example.txt");if(!outFile.is_open()) {exit(EXIT_FAILURE);}int count = 1;int x;for(int i = 0; i < 10; ++i) {cin >> x;outFile << x;if(i==5)outFile << endl;elseoutFile << " "; }outFile.close();return 0;
}声明并实现了一个矩形类，表示矩形。Rectangle类包括：
double类型的私有数据成员width和height，表示矩形的宽和高。
带默认参数的构造函数，将矩形的宽和高设置为给定的参数。宽和高的默认参数值为1。
更改器函数setWidth和setHeight，分别用于修改矩形的宽和高。
访问器函数getWidth和getHeight，分别用于访问矩形的宽和高。
成员函数computeArea，返回矩形的面积。
成员函数computePerimeter，返回矩形的周长。
创建5个Rectangle对象（每个Rectangle对象的宽和高分别为1、2、3、4、5）并将它们写入二进制文件object.dat中。修改第3个对象的宽为10、高为3.5，再把修改后的该对象写回文件原位置。
【输入】
没有输入。
【输出】
生成文件object.dat
#include<iostream>
#include<fstream>using namespace std;class Rectangle {private:double width;double height;public:Rectangle(double w = 1, double h = 1) {width = w;height = h;}double getWidth() {return width;}double getHeight() {return height;}void setWidth(double newWidth) {width = newWidth;} void setHeight(double newHeight) {height = newHeight;}double computeArea() {return width * height;}double computePerimeter() {return 2 * (height + width);}};
int main () {ofstream fout;ifstream fin;fout.open("object.dat", ios::out | ios::binary);Rectangle r[5];for (int i = 0; i < 5; i++) {r[i] = Rectangle(i + 1, i + 1);}fout.write((const char *)(&r), sizeof(r));fout.close();Rectangle res[5];fin.open("object.dat", ios::in | ios::binary);fin.read(reinterpret_cast<char *>(res), sizeof(res));res[2].setHeight(3.5);res[2].setWidth(10);fin.close();fout.open("object.dat", ios::out | ios::binary);fout.write((const char *)(&r), sizeof(r));fout.close();return 0;
}需要计算一些学生的加权平均分。给定输入文件gpa.dat，文件中每个学生的信息都由两行内容组成。第一行是学生姓名，第二行是他几门课的成绩。下面是某个输入文件gpa.dat的内容：
张三
3 2.8 4 3.9 3 3.1
李思
3 3.9 3 4.0 4 3.9
王武
2 4.0 3 3.6 4 3.8 1 2.8
刘刘
3 3.0 4 2.9 3 3.2 2 2.5
#include<bits/stdc++.h>
#include<unordered_map>
#define ll long long
#define ull unsigned long long
#define IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;const ll inf = 0x3f3f3f3f;
const double eps = 1e-4;
const ll N = 2e5 + 5;
const int mod = 1e9 + 7;signed main()
{ifstream infile;infile.open("gpa.dat");string s;map<string, ll> mp;double mx = 0, mi = inf;//while(getline(cin, s))while (getline(infile, s)){string sc;//getline(cin, sc);getline(infile, sc);double aver = 0, sumxf = 0, cnt = 0;for (ll i = 0; i < sc.size();){//cnt++;sumxf += sc[i] - '0';aver += (sc[i] - '0') * (sc[i + 2] - '0' + (sc[i + 4] - '0') * 0.1);i += 6;}//aver /= cnt;double ans = aver / sumxf;mi = min(ans, mi);mx = max(ans, mx);cout << "GPA for " << s << " = " << fixed << setprecision(2) << ans << '\n';}cout << "max GPA" << " = " << mx << '\n';cout << "min GPA" << " = " << mi << '\n';infile.close();cout << mp.size();return 0;
}处理日志文件，日志文件的储存格式为“年/月/日 时：分：秒 用户名 操作”。
日志文件有多条记录：
2015/4/218：00：33 37c3b6b58c6ac3 LOGIN
2015/4/218：15：35 11734e186f24fe4c LOGIN
2015/4/218：34：57 9f3cf331d19a9f LOGIN
2015/4/219：00：29 389bcca2159f5de7 LOGIN
2015/4/219：08：29 c3bde693fdb3c3d LOGIN
【输入示例】
无
【输出示例】
123
#include<iostream>
#include<fstream>
#include<string>
#include<set>
using namespace std;
set<string> st;
string s;
int main () {ifstream ifs;ifs.open("log.txt");while (ifs >> s) {ifs >> s;ifs >> s;st.insert(s);ifs>> s;}cout << st.size();ifs.close();return 0;
}给定文件hours.txt，其中包含每个员工工作时间的记录。每一行表示一周的工作时间。每周有7天，所以每行最多有7个数字。规定每周从周一开始，文件中的每一行都是从周一的工作小时数开始，后面是周二，等等，周日的数字放在这一行的最后。每行中的数字可以少于7个，因为员工并不是每天都要工作。下面是文件hours.txt的内容：
8 8 8 8 8
8 4 8 4 4 4 8
4 8 4 8
3 0 0 8 6 4 4
8 8
0 0 8 8
8 8 8 4 4 4
#include<bits/stdc++.h>
#include<unordered_map>
#define ll long long
#define ull unsigned long long
#define IOS ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;const ll inf = 0x3f3f3f3f;
const double eps = 1e-4;
const ll N = 2e5 + 5;
const int mod = 1e9 + 7;signed main()
{fstream f;f.open("hours.txt");ll a[10] = { 0 };string s;while (getline(f, s)){s += ' ';ll num = 0, ans = 0;for (ll i = -1, cnt = 1; i < (int)s.size() - 1; cnt++){num = 0;while (s[++i] != ' ')num = num * 10 + s[i] - '0';ans += num;a[cnt] += num;}cout << "Total hours = " << ans << '\n';}cout << '\n';cout << "Mon hours = " << a[1] << '\n';cout << "Tue hours = " << a[2] << '\n';cout << "Wed hours = " << a[3] << '\n';cout << "Thu hours = " << a[4] << '\n';cout << "Fri hours = " << a[5] << '\n';cout << "Sat hours = " << a[6] << '\n';cout << "Sun hours = " << a[7] << '\n';cout << "Total hours = " << a[1] + a[2] + a[3] + a[4] + a[5] + a[6] + a[7];return 0;
}
