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最新推荐文章于 2023-04-16 23:33:31 发布

转载最新推荐文章于 2023-04-16 23:33:31 发布 · 69 阅读

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原文链接：http://www.cnblogs.com/fffffaaaaaa/p/9080006.html

本文通过几个具体的C++程序实例，介绍了如何使用类、对象、向量等特性来实现特定的功能，包括喜好列表的互换、内存管理、矩阵操作、骰子随机数生成及用户管理系统的设计。

 1 #include<iostream>
 2 #include<vector>
 3 #include<string>
 4 using namespace std;
 5 string myfavorite[7]={"book", "music", "film", "paintings","anime","sport","sportsman"};//函数声明
 6 void output1(vector<string> &);
 7 void output2(vector<string> &);
 8 void swapl(string s1,string s2);
 9   int main()
10 {
11     vector<string> likes, dislikes; // 创建vector<string>对象likes和dislikes
12     likes.push_back("《高等数学》");
13     likes.push_back("navada");
14     likes.push_back("《复仇者联盟》");
15     likes.push_back("向日葵");
16     likes.push_back("《哆啦A梦》");
17     likes.push_back("羽毛球");
18     likes.push_back("梅西");
19     cout << "-----I like these-----" << endl;
20     output1(likes);//调用函数输出vector数组对象like的元素值
21     dislikes.push_back("语文");
22     dislikes.push_back("低沉音乐");
23     dislikes.push_back("烂片");
24     dislikes.push_back("无");
25     dislikes.push_back("大胃王");
26     dislikes.push_back("冰球");
27     dislikes.push_back("无");
28     cout << "-----I dislike these-----" << endl;
29     output2(dislikes);//调用函数输出vector数组对象dislike的元素值
30     for(unsigned int i=0;i<likes.size();i++)
31     {
32         swapl(likes[i],dislikes[i]);
33     }
34     cout << "-----I like these-----" << endl;
35     output1(likes);
36     cout << "-----I dislike these-----" << endl;
37     output2(dislikes);
38     return 0;
39 
40 }
41 //以下标的方式输出
42 void output1(vector<string> &v)
43 {
44     for(unsigned int i=0;i<v.size();i++)
45     {
46         cout<<myfavorite[i]<<":"<<v[i]<<" "<<endl;
47     }
48 }
49 //以迭代器的方式输出
50 void output2(vector<string> &v)
51 {
52     int a=0;
53     for(auto i=v.begin();i<v.end();i++)
54     {
55         cout<<myfavorite[a++]<<":"<<*i<<" "<<endl;
56     }
57 }
58 void swapl(string s1,string s2){
59   string temp=s1;
60   s1=s2;
61   s2=temp;
62 }

 1 #include<iostream>
 2 using namespace std;
 3 int fn1(){
 4     int *p=new int(5);
 5     
 6     return *p;
 7     delete p;//在定义了new后没有使用delete进行释放内存，回导致问题的出现 
 8 }
 9 int main(){
10     int a=fn1();
11     cout<<"the value of a is:"<<a;
12     return 0;
13     
14 }

 1 #include<iostream>
 2 using namespace std;
 3 int main()
 4 {
 5     int *p;
 6     int a；
 7    p=&a；
 8    p=8
 9     cout<<"The value at p: "<<*p;
10     return 0;
11 }

main

#include <iostream>
#include"Matrix.h"
using namespace std;
int main()
{
    Matrix A(2);
    Matrix B(2,3);
    float a[4]={1,2,3,4};
    A.setMatrix(a);
    A.printMatrix();
    return 0;
}

Matrix.h

#ifndef MATRIX_H_INCLUDED
#define MATRIX_H_INCLUDED
class Matrix{
public:
    Matrix(int n);//构造函数，构造n*n矩阵
    Matrix(int n,int m);//n*m矩阵
    Matrix(const Matrix &x);//复制构造函数，使用已有矩阵x构造
    ~Matrix;
    void setMatrix(const float *pvalue);//矩阵赋初值，用pvalue指向的内存块数据为矩阵赋初值
    void printMatrix()const;//显示举证
    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i行j列元素
    void setElement(int i,int j,int value);//设置矩阵第i行第j列的元素为value
    inline int getLines()const;//返回矩阵行数
    {
        return lines;
    }
    inline int getCols()const;//返回矩阵列数
    {
        return cols;
    }
private:
    int lines;
    int cols;
    float *p;//存放矩阵数据内存的首地址


};
inline float &element(int i,int j)
{
    float &r=p[(i-1)*cols+j-1];
        return r;
}
inline float element(int i, int j) const
{
    float r=p[(i-1)*cols+j-1];
        return r;
}


#endif // MATRIX_H_INCLUDED

Matrix.cpp

#include<iostream>
#include"Matrix.h"
using namespace std;

Matrix::Matrix(int n):lines(n),cols(n)
{
    p=new float[lines*cols];
}
Matrix::Matrix(int n,int m):lines(n),cols(m)
{
    p=new float[lines*cols];
}
Matrix::~Matrix()
{
    delete p;
}
void Matrix::printMatrix()const
{
    for(int i=0;i<lines;i++)
    {
        for(int j=0;j<cols;j++)
            cout<<p[i*cols+j]<<" ";
        cout<<endl;
    }
}
void Matrix::setMatrix(const float *pvalue)
{
    for(int i=0;i<lines;i++)
    {
        for(int j=0;j<cols;j++)
            p[i*cols+j]=pvalue[i*cols+j];
    }
}

　　期中考试

#include <iostream>
#include<cstdlib>
#include<cmath>
#include<ctime>
using namespace std;
class Dice
{
    public:
        Dice(int n);
        int cast();
    protected:
        int sides;
};
Dice::Dice(int n):sides(n){}
Dice::cast()
{
    struct timeb timeSeed;
    ftime(&timeSeed);
    srand(timeSeed.time * 1000 + timeSeed.millitm);

    int result;
    result=1+(rand()%sides-1);
    return result;
}
int main()
{
    double times,probability;
    Dice a(40);
    for(int i=0;i<500;i++){
        int eachtime=a.cast();
        cout<<eachtime<<" ";
        if(eachtime==21)
            times++;
    }
    probability=times/500;
    cout<<"概率是"<< probability<<endl;
    return 0;
}

main

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


using namespace std;
int main()
{
   vector<user>users;
    int count = 0;
    while (true) {
        cout << "创建用户输1，修改新用户密码输2，打印用户信息输3，打印当前ID输4，退出输0" << endl;
        int number;
        cin >> number;
        if (number == 1) {
            user u1;
            users.push_back(u1);
            count++;
        }
        else if (number == 2) {
            users[count - 1].changepassword();
        }
        else if (number == 3) {
            users[count - 1].print();
        }
        else if (number == 4) {
            users[count - 1].printcurrentid();
            users[count - 1].print();
        }
        else if (number == 0) {
            break;
        }
    }
    return 0;
}

　　user。h

#ifndef USER_H_INCLUDED
#define USER_H_INCLUDED
#include <string>
#include <vector>
#include <iostream>
using namespace std;
 class user
 {
  public:
    user();
     ~user();
    void print();
    void changepassword();
    void printcurrentid();
  private:
    int id;
    string name;
    string password;
    static int currentid;

 };


#endif // USER_H_INCLUDED

　　user。cpp

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

#include <iostream>
using namespace std;

int user::currentid = 999;
user::user() {
    cout << "请输入用户名：";
    cin >> name;
    password = "111111";
    currentid++;
    id = currentid;
}
user::~user(){}
void user::print() {
    cout << "用户ID为：" << id << endl;
    cout << "用户名为：" << name << endl;
    cout << "密码为：" << password << endl;
}
void user::changepassword(){
 int count=0;
    while(count<3)
    {
      string a;
      cout<<"plesse input psssword"<<endl;
      cin>>a;
      if(a==password)
        {cout<<right;
        cin>>a;
        password=a;
        break;
        }
      else
        cout<<"错了请重输"<<endl;
        count++;

    }
    if (count == 3)
    {
        cout << "请稍后再试" << endl;
    }
}
void user::printcurrentid(){
 cout << "currentID:" << currentid << endl;
}

main

#include <iostream>
#include<vector>
#include"Book.h"
using namespace std;

int main()
{
    vector<Book> books;
    string cx,cv;
    float pl;
    while(cin>>cx>>cv>>pl)
    {
        Book a(cx,cv,pl);
        books.push_back(a);
    }
    for(int i=0;i<books.size();i++)
    {
        books[i].print();
    }
    return 0;
}

　　book.h

#ifndef BOOK_H_INCLUDED
#define BOOK_H_INCLUDED
#include<iostream>
#include<string>
#include<cstring>
using namespace std;
class Book
{
    public:
        Book(string a,string c,float v);
        void print();
    private:
        string isbn;
        string title;
        double price;
};


#endif // BOOK_H_INCLUDED

　　book.cpp

#include "Book.h"
Book::Book(string a,string b,float c):isbn(a),title(b),price(c){}
void Book::print()
{
    cout<<"出版编号："<<isbn<<"    "<<"书名："<<title<<"    "<<"定价："<<price<<"  RMB"<<endl;
}

转载于:https://www.cnblogs.com/fffffaaaaaa/p/9080006.html