【实验5】类和对象-3

实验1：

#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>likes, dislikes; // 创建vector<string>对象likes和dislikes
    likes.push_back("book");
    likes.push_back("music");
    likes.push_back("film");
    likes.push_back("paintings");
    likes.push_back("anime");
    likes.push_back("sportsman");
    likes.push_back("etc");    
    // 为vector<string>数组对象likes添加元素值 ( favorite book, music, film, paintings,anime,sport,sportsman,etc) 

    cout << "-----I like these-----" << endl;
    // 调用子函数输出vector<string>数组对象likes的元素值 
    output1(likes);
    
    dislikes.push_back("book'");
    dislikes.push_back("music'");
    dislikes.push_back("film'");
    dislikes.push_back("paintings'");
    dislikes.push_back("anime'");
    dislikes.push_back("sportsman'");
    dislikes.push_back("etc'");    
    // 为vector<string>数组对象dislikes添加元素值 
    
    
    cout << "-----I dislike these-----" << endl;
    // 调用子函数输出vector<string>数组对象dislikes的元素值 
    output1(dislikes);
    
    
    // 交换vector<string>对象likes和dislikes的元素值 
    likes.swap(dislikes);
    
    
    cout << "-----I likes these-----" << endl;
    // 调用子函数输出vector<string>数组对象likes的元素值 
    output2(likes);
    
    cout << "-----I dislikes these-----" << endl;
    // 调用子函数输出vector<string>数组对象dislikes的元素值 
    output2(dislikes); 
                        
    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) 
{
    for(vector<string>::iterator i = v.begin() ; i<v.end() ; ++i)//使用迭代器访问vector中的元素
        cout<<*i<<" ";
    cout<<endl;
}

ex3

实验2：

#include <iostream>
using namespace std;
int main()
{
    int *p;
//    *p=9;                                  指针指向不明 
    p=new int(9);
    cout<<"The value at p: "<<*p; 
    delete p;
    return 0;
}

2.1

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

2.2

实验3：

#include <iostream>
#include "matrix.h"

using namespace std;

int main()
{
    Matrix x1(2, 5);
    x1.printMatrix();
    cout << endl;
    Matrix x2(2, 5);
    float s[2*5] = { 1,2,3,4,5,6,7,8,9,10 };
    x2.setMatrix(s);
    x2.printMatrix();
    return 0;
}

main.cpp

#include <iostream>
#include "matrix.h"

using namespace std;

Matrix::Matrix(int n)
{
    lines = n;
    cols = n;
    p = new float[lines*cols];
    for (int i = 0; i < lines*cols; ++i)
        p[i] = 0;
}

Matrix::Matrix(int n, int m)
{
    lines = n;
    cols = m;
    p = new float[lines*cols];
    for (int i = 0; i < lines*cols; ++i)
        p[i] = 0;
}

Matrix::Matrix(const Matrix &X)
{
    lines = X.lines;
    cols = X.cols;
    p = new float[lines*cols];
    for (int i = 0; i < lines*cols; ++i)
        p[i] = X.p[i];
}

Matrix::~Matrix()
{
    delete[] p;
}

void Matrix::setMatrix(const float *pvalue)
{
    for (int i = 0; i < lines*cols; ++i)
        p[i] = pvalue[i];
}

void Matrix::printMatrix() const
{
    for (int i = 0; i < cols; ++i)
    {
        for (int j = 0; j < lines; ++j)
            cout << p[i*lines + j] << " ";
        cout << endl;
    }
}

float &Matrix::element(int i, int j)
{
    return *(p + i * lines + j);
}

float Matrix::element(int i, int j) const
{
    return p[i*lines + j];
}

void Matrix::setElement(int i, int j, int value)
{
    p[i*lines + j] = static_cast<float>(value);
}

int Matrix::getLines() const
{
    return lines;
}

int Matrix::getCols() const
{
    return cols;
}

matrix.cpp

#ifndef MATRIX_H
#define MATRIX_H
class Matrix {
    public:
        Matrix(int n); // 构造函数，构造一个n*n的矩阵 
        Matrix(int n, int m); // 构造函数，构造一个n*m的矩阵 
        Matrix(const Matrix &X); // 复制构造函数，使用已有的矩阵X构造 
        ~Matrix(); //析构函数 
        void setMatrix(const float *pvalue); // 矩阵赋初值,用pvalue指向的内存块数据为矩阵赋值 
        void printMatrix() const; // 显示矩阵
        inline float &element(int i, int j); //返回矩阵第i行第j列元素的引用
        inline float element(int i, int j) const;// 返回矩阵第i行第j列元素的值 
        void setElement(int i, int j, int value); //设置矩阵第i行第j列元素值为value
        inline int getLines() const; //返回矩阵行数 
        inline int  getCols() const; //返回矩阵列数 
    private:
        int lines;    // 矩阵行数
        int cols;      // 矩阵列数 
        float *p;   // 指向存放矩阵数据的内存块的首地址 
};
#endif

matrix.h

实验4：

4.1：

#include <iostream>
#include "dice.h"

using namespace std;

int main()
{
    int n;
    int k = 0;                      //抽中次数
    cout << "请输入班级人数：";
    cin >> n;
    Dice d1(n);
    for (int i = 1; i <= 500; ++i)
    {
        if ((d1.cast() + 1) == 40)
            ++k;
    }
    cout << "被抽中几率为：" << static_cast<double>(k) / 500.0000 << endl;
    return 0;
}

main.cpp

#pragma once

class Dice
{
private:
    int sides;
public:
    Dice(int);
    int cast();
};

dice.h

#include <iostream>
#include "dice.h"
#include <cstdlib>
#include <ctime>

Dice::Dice(int n)
{
    sides = n;
}

int Dice::cast()
{
    srand(time(NULL)+rand());
    return (rand() % sides);
}

dice.cpp

4.2:

#include <iostream>
#include "user.h"

using namespace std;

int main()
{
    char x1[25];
    cin >> x1;
    User user1(x1);
    user1.puts();
    user1.change_password();
    user1.puts();
    return 0;
}

main.cpp

#include <iostream>
#include <string>
#include "user.h"

using namespace std;

User::User(char *p)
{
    static int CurrentID = 0;
    ++CurrentID;
    id = CurrentID;
    strcpy_s(name, p);
    strcpy_s(password, "111111");
}

void User::puts()
{
    cout << "CurrentID: " << id << endl;
    cout << "id: " << id << " , name: " << name << " , password: " << password << endl;
}

void User::change_password()
{
    int i;
    for (i = 1; i <= 3; ++i)
    {
        cout << "请输入原密码：";
        char a[25];
        cin >> a;
        if (strcmp(a, password) == 0)
            break;
        else
            cout << "密码错误，重新输入（还有" << (3 - i) << "次机会）" << endl;
    }
    if (i == 4)
        cout << "输入错误次数过多，请稍后再尝试！" << endl;
    else
    {
        cout << "请输入新密码：";
        char b[25];
        cin >> b;
        strcpy_s(password, b);
    }
}

user.cpp

#pragma once

class  User
{
public:
     User(char *);
     void puts();
     void change_password();
private:
    int id;
    char name[25];
    char password[25];
};

user.h

4.3:

#include "book.h"
#include <iostream> 
#include <string>

using namespace std;

// 构造函数
Book::Book(string isbnX, string titleX, float priceX)
{
    isbn = isbnX;
    title = titleX;
    price = priceX;
}


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

book.cpp

#include "book.h"
#include <vector>
#include <iostream>

using namespace std;

int main()
{
    // 定义一个vector<Book>类对象
    vector<Book> book;
     
    string isbn, title;
    float price;
    
    // 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） 
    while(cin >> isbn >> title >> price)
    {
        Book x(isbn, title, price);
        book.push_back(x);
    }
    
    
    // 输出入库所有图书信息
    for (int i = 0; i < book.size(); ++i)
    {
        book[i].print();
    }
    
    
    return 0;
}

main.cpp

#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.h

我自己大致认识到自己的编程速度不够快，应该是对相关内容的掌握不够牢固，而且编程训练不够多。前路还很漫长……

通过这次作业，我对函数模板的掌握更加到位了，但还有许多不太清楚的地方，在今后一定能一一克服。