实验5

#include <iostream>
#include <vector>
#include <string>
using namespace std;

// 函数声明 
void output1(vector<string> &);  
void output2(vector<string> &);  

int main()
{
    vector<string>like, dislike; // 创建vector<string>对象likes和dislikes
    like.push_back("favorite book") ;
    like.push_back("music");    
    like.push_back("film");    // 为vector<string>数组对象likes添加元素值 ( favorite book, music, film, paintings,anime,sport,sportsman,etc) 
    like.push_back("paintings");// 补足代码 
    like.push_back("anime");
    like.push_back("sport");    // 。。。 
    like.push_back("sportsman");
    cout << "-----I like these-----" << endl;
     output1(like);// 调用子函数输出vector<string>数组对象likes的元素值 
    cout<<"what do you dislike?"<<endl;// 为vector<string>数组对象dislikes添加元素值 
    string s1;// 补足代码 
    while(true)
    {    
        getline(cin,s1);
        if(s1!="etc")
        dislike.push_back(s1);
        else break;
    } 
    cout << "-----I dislike these-----" << endl;
     output2(dislike);// 调用子函数输出vector<string>数组对象dislikes的元素值 
    like.swap(dislike);// 交换vector<string>对象likes和dislikes的元素值  
        cout << "-----I likes these-----" << endl;
     output1(like);// 调用子函数输出vector<string>数组对象likes的元素值 
    cout << "-----I dislikes these-----" << endl;
     output2(dislike);// 调用子函数输出vector<string>数组对象dislikes的元素值 
    return 0;
}


// 函数实现 
// 以下标方式输出vector<string>数组对象v的元素值  
void output1(vector<string> &v) 
{
    for(int  i=0;i<v.size();i++)
    cout<<v[i]<<" ";
    cout<<endl;
}

// 函数实现
// 以迭代器方式输出vector<string>数组对象v的元素值 
void output2(vector<string> &v) 
{
    vector<string> ::iterator it;
    for(it=v.begin();it!=v.end();it++)
    cout<<*it<<" ";
    cout<<endl;
}

#include<iostream> 
using namespace std;
int main()
{
    int *p;
        *p=9;//  编译器可以编译通过，但这种用法不对 
     cout<<"the value of a is :"<<*p;
     return 0;
}
//定义指针后必须先赋值 在引用  

#include<iostream> 
using namespace std;
int main()
{   
    int a,*p=&a;
        *p=9;
     cout<<"the value of a is :"<<*p;
     return 0;
}

#include<iostream>
using namespace std;
int fn1()
{
    int *p=new int (5);
    return *p;
}
int main()
{
    int a=fn1();
    cout<<"the value of a is:"<<a<<endl;
    return 0;
}//编译依旧可以正确运行 但用new分配的内存必须用delete 加以释放  

#include<iostream>
using namespace std;
int fn1()
{
    int *p=new int (5);
    return *p;
    delete p; 
}
int main()
{
    int a=fn1();
    cout<<"the value of a is:"<<a<<endl;
    return 0;
}

#include<iostream> 
#include<cstdlib>
#include<ctime>
using namespace std;
class Dice
{
    public: Dice(int s0=0);
            int cast();
    private: int sides;            
};
Dice::Dice(int s0):sides(s0){
}
int Dice::cast()
{
    int r=rand()%sides+1;
    return r;
}
int main()
{
    Dice mydice(40);
    srand(time(NULL));
    double m=0,p;
    for(int t=0;t<500;t++)    
    { 
       if(mydice.cast()==39)
        m++;
    }
    p=m/500;
    cout<<p<<endl;
    return 0;    
}

user.h
#ifndef USER_H
#define USER_H
#include<string> 
using namespace std;
class user
{
    public:
           user(string namex, string passwordx="111111");
           void print();
           void changenumber();
           void showcurrentID();
    private:
            int id;
            string name,password;
           static int CurrentID;
};
#endif

user.cpp
#include<iostream>
#include"user.h"
#include<string>
using namespace std;
user::user(string namex, string passwordx):name(namex),password(passwordx){
    id=++CurrentID;
} 
void user::changenumber()
{   int i=0;
    string m,n;
    while(true)
    {    cout<<"输入旧密码："<<endl; 
        cin>>m;
        if(m==password)
        {
            cin>>n;
            password=n;
            cout<<"new password:"<<password<<endl;
            break;
        }
        else {
            cout<<"error!please try again!"<<endl;
            i++;
            if(i<3) 
            continue;
            else {
            cout<<"please try later!"<<endl;
            break;    
           }
        }
    }
}
void user::print()
{
    cout<<"id:"<<id<<endl;
    cout<<"name:"<<name<<endl;
    cout<<"password:"<<password<<endl;
}
   void user::showcurrentID()
{
    cout<<CurrentID <<endl;
    cout<<"id:"<<id<<endl;
    cout<<"name:"<<name<<endl;
    cout<<"password:"<<password<<endl;
}
int user::CurrentID=999;

#include<iostream>
#include"user.h"
#include<string>
using namespace std;
int main()
{
    user u1("zzy","5201314");
    u1.print();
    u1.changenumber();
    u1.showcurrentID();
    return 0;
}

book.h
#ifndef BOOK_H
#define BOOK_H

#include <string>
using std::string;

class Book {
    public:
        Book(string isbnX, string titleX, float priceX);  //构造函数  
        void print(); // 打印图书信息 
    private:
        string isbn;
        string title;
        float price;
};
#endif

book.cpp
#include "book.h"
#include <iostream> 
#include <string>
using namespace std;
 Book::Book(string isbnX, string titleX, float priceX):isbn(isbnX),title(titleX),price(priceX){
 }// 构造函数


void Book::print()
{ 
  cout<<"isbn:" <<isbn<<endl;
  cout<<"title:"<<title<<endl;
  cout<<"price:"<<price<<endl;
}// 打印图书信息
// 补足程序 
// ...

main.cpp
#include "book.h"
#include <vector>
#include <iostream>
using namespace std;

int main()
{
    vector<Book>mybooks;// 定义一个vector<Book>类对象 
    string isbn, title;
    float price;
    while(true)
    {  
       if(cin>>isbn>>title>>price)
     { 
       if(isbn=="0"&&title=="0"&&price==0)
        break;
        else {
           Book book(isbn,title,price);
           mybooks.push_back(book);
         }
     }
    }
    for(int i=0;i<mybooks.size();i++)
    mybooks[i].print();
    // 录入图书信息，构造图书对象，并添加到前面定义的vector<Book>类对象中
    // 循环录入，直到按下Ctrl+Z时为止 (也可以自行定义录入结束方式） 
    
    
    return 0;
}