電商專業(yè)學(xué)習(xí)嵌入式軟件開發(fā)第六十一天

  • C++第七天

今天主要講vector類模板和迭代器,以及軟件qt的大概使用方法。今天代碼的意思不難理解,就是自己寫不出來，尤其是今天留的兩道作業(yè),第一題是剛講過,但是整理不出頭緒。

#include <iostream>
#include <vector>
using namespace std;
//vector:是一個(gè)類模板,空間連續(xù)，并且空間自動(dòng)增長,可以把它理解為空間自動(dòng)增長的數(shù)組
void print(vector<int> &vec)
{
    //迭代器，類似于指針
    vector<int>::iterator iter;
    iter = vec.begin();
    for (; iter != vec.end(); iter++)
    {
        cout << *iter << ' ';
    }
    cout << endl;
}
int main()
{
    vector<int> vec;
    //vector最開始空間為0,不能直接通過下標(biāo)進(jìn)行訪問
    //vec[100] = 90;  // X
    //push_back:會(huì)自動(dòng)申請(qǐng)空間,與string分配空間的策略一樣
    vec.push_back(89);
    cout << "size:" << vec.size() <<" capacity:"<<vec.capacity()<<'\n';
    
    vec.push_back(99);
    cout << "size:" << vec.size() <<" capacity:"<<vec.capacity()<<'\n';
    
    vec.push_back(79);
    cout << "size:" << vec.size() <<" capacity:"<<vec.capacity()<<'\n';
    
    vec.push_back(69);
    cout << "size:" << vec.size() <<" capacity:"<<vec.capacity()<<'\n';
    
    vec.push_back(89);
    cout << "size:" << vec.size() <<" capacity:"<<vec.capacity()<<'\n';
    
    vec.push_back(109);
    cout << "size:" << vec.size() <<" capacity:"<<vec.capacity()<<'\n';
    print(vec);
#if 0
    for (int i=0; i < vec.size(); i++)
    {
        cout << vec[i] << ' ';
    }
    cout << endl;
#endif
    cout << "Hello World!" << endl;
    return 0;
}

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

class Student{};
typedef vector<Student *> STUVEC;
int main(void)
{
    STUVEC vec;
    vec.push_back(new Student);
    vec.push_back(new Student);
    vec.push_back(new Student);

    STUVEC::iterator iter = vec.begin();

    return 0;
}

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

class Student
{
public:
    Student(string name="", float score=0)
    {
        cout << "Student(string,float)\n";
    }
    Student(const Student &other)
    {
        cout << "Student(const Student &)\n";
    }
    ~Student(){cout << "~Student()\n";}
private:
    string m_strName;
    float m_fScore;
};
int main()
{
    vector<Student> vec;
    Student aa("aa", 11);
    vec.push_back(aa);
    
    Student bb("bb", 22);
    vec.push_back(bb);

    Student cc("cc", 33);
    vec.push_back(cc);

    Student dd("dd", 44);
    vec.push_back(dd);

    Student ee("ee", 55);
    vec.push_back(ee);

    Student ff("ff", 66);
    vec.push_back(ff);

    Student gg("gg", 77);
    vec.push_back(gg);

    cout << "Hello World!" << endl;
    return 0;
}

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

class Student
{
public:
    Student(string name="")
    {
        m_strName = name;
    }
    const string &getName(){return m_strName;}
private:
    string m_strName;
};
int main(void)
{
    //vector<Student *> vec;
    //vector<Student *> vec[1024];
    string strName;
    vector<vector<Student *> > vec;
    for (int i = 0; i < 3; i++)
    {
        vector<Student *> tmp;
        for (int j = 0; j < 2; j++)
        {
            cout << "input name:";
            cin >> strName;
            tmp.push_back(new Student(strName));
        }
        vec.push_back(tmp);
    }
    for (int i = 0; i < 3; i++)
    {
        for (int j = 0; j < 2; j++)
        {
            cout << vec[i][j]->getName() << ' ';
        }
        cout << '\n';
    }
    return 0;
}

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

class Student
{
public:
    Student(string name="", float score=0)
    {
        cout << "Student(string,float)\n";
    }
    Student(const Student &other)
    {
        cout << "Student(const Student &)\n";
    }
    ~Student(){cout << "~Student()\n";}
private:
    string m_strName;
    float m_fScore;
};
int main()
{
    vector<Student*> vec;
    vec.push_back(new Student("aa", 11));
    vec.push_back(new Student("bb", 22));
    vec.push_back(new Student("cc", 33));
    vec.push_back(new Student("dd", 44));
    vec.push_back(new Student("ee", 55));
    vec.push_back(new Student("ff", 66));
    vec.push_back(new Student("gg", 77));
    vector<Student*>::iterator iter;
    iter = vec.begin();
    for (; iter != vec.end(); iter++)
    {
        delete (*iter);
    }   
    vec.clear();
    cout << "Hello World!" << endl;
    return 0;
}

#include <iostream>
#include <vector>
using namespace std;
//vector:是一個(gè)類模板,空間連續(xù)，并且空間自動(dòng)增長,可以把它理解為空間自動(dòng)增長的數(shù)組

void print(vector<int> &vec)
{
    //迭代器，類似于指針
    vector<int>::iterator iter;
    iter = vec.begin();
    for (; iter != vec.end(); iter++)
    {
        cout << *iter << ' ';
    }
    cout << endl;
}
int main()
{
    //vector<int> vec(32, 888);
    vector<int> vec(32);
    vec.clear();
    cout << vec.size() << ' ' << vec.capacity() << endl;
    print(vec);

    cout << "Hello World!" << endl;
    return 0;
}

#include <iostream>
#include <vector>
using namespace std;
//vector:是一個(gè)類模板,空間連續(xù)，并且空間自動(dòng)增長,可以把它理解為空間自動(dòng)增長的數(shù)組

void print(vector<int> &vec)
{
    //迭代器，類似于指針
    vector<int>::iterator iter;
    iter = vec.begin();
    for (; iter != vec.end(); iter++)
    {
        cout << *iter << ' ';
    }
    cout << endl;
}
int main()
{
    int a[7] = {19, 67, 89, 3, 16, 22, 15};
    vector<int> vec(a, a+7);  //[)
    print(vec);
    //vec.resize(3);
    //vec.resize(13);
    vec.resize(13, 888);
    print(vec);
#if 0
    vec.assign(3, 888);
    print(vec);
#endif
    cout << vec.size() << ' ' << vec.capacity() << endl;

    cout << "Hello World!" << endl;
    return 0;
}

#include <iostream>
#include <vector>
using namespace std;
//vector:是一個(gè)類模板,空間連續(xù)，并且空間自動(dòng)增長,可以把它理解為空間自動(dòng)增長的數(shù)組

void print(vector<int> &vec)
{
    //迭代器，類似于指針
    vector<int>::iterator iter;
    iter = vec.begin();
    for (; iter != vec.end(); iter++)
    {
        cout << *iter << ' ';
    }
    cout << endl;
}
int main()
{
    vector<int> vec;
    vec.reserve(1024);
    cout << "size:" << vec.size() << " capacity:"<<vec.capacity()<<endl;
    print(vec);
    return 0;
}

#include <iostream>
#include <vector>
using namespace std;
//vector:是一個(gè)類模板,空間連續(xù)，并且空間自動(dòng)增長,可以把它理解為空間自動(dòng)增長的數(shù)組

void print(vector<int> &vec)
{
    //迭代器，類似于指針
    vector<int>::iterator iter;
    iter = vec.begin();
    for (; iter != vec.end(); iter++)
    {
        cout << *iter << ' ';
    }
    cout << endl;
}
int main()
{
    int a[7] = {19, 67, 89, 3, 16, 22, 15};
    vector<int> vec(a, a+7);  //[)
    print(vec);
    vector<int>::iterator iter = vec.begin();
    iter = iter+3;
    vec.insert(iter, 888);
    print(vec);
    cout << "----------------\n";
    iter = vec.begin();
    for (;iter != vec.end();)
    {
        if (0 != (*iter)%2)
        {
            //對(duì)容器進(jìn)行增刪后，所有迭代器失效
            //必須對(duì)迭代器進(jìn)行重新賦值
            //erase返回值為下一個(gè)元素的迭代器
            iter = vec.erase(iter);//對(duì)容器進(jìn)行刪除
        }
        else
        {
            iter++;
        }
    }
    print(vec);
    cout << "Hello World!" << endl;
    return 0;
}

作業(yè)：
1、a.動(dòng)態(tài)生成多個(gè)學(xué)生對(duì)象,將學(xué)生對(duì)象的指針放入容器中，然后將容器中的數(shù)據(jù)寫入文件中
b.將文件中的學(xué)生數(shù)據(jù)讀取出來放入容器中并顯示
2、寫一個(gè)類模板，用來對(duì)不同類型的數(shù)據(jù)進(jìn)行排序

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