一些簡單的c++問題（2.0）目錄Constructor & Destructor

目錄

• 目錄
• Constructor & Destructor
  • • 問題描述
    • 代碼實作
• 輸出和最小的子數列
  • • 問題描述
    • 程式代碼
    • Q
• 求和：fabonaci數列前20
  • • 代碼
• MyArray
  • • 代碼
• noname1
  • • 代碼
• noname2
  • • 代碼

Constructor & Destructor

問題描述

構造函數與析構函數

代碼實作

#include <iostream>
using namespace std;
class coordinate
{
public :
    coordinate (int x1,int y1) //coordinate:坐标
    {
        x=x1;
        y=y1;

    }

coordinate(coordinate &p);
~coordinate()
{
    cout<<"Destructor is called\n";
}
int getx()
{
    return x;
}
int gety()
{
    return y;
}
private:
    int x,y;
};
coordinate::coordinate(coordinate &p)
{
    x=p.x;
    y=p.y;
    cout<<"copy-initialization constructor is called\n";

}
int  main()
{
    coordinate p1(,);
    coordinate p2(p1);
    coordinate p3=p2;
    cout<<"p3=("<<p3.getx()<<","<<p3.gety()<<")\n";
    return ;
}
           

輸出和最小的子數列

問題描述

輸入一個數列，輸出和最小的子數列

程式代碼

//輸入一組數列，求出和最小的子數列，并輸出最小和
#include<iostream>
using namespace std;
const int n = ;
void swap(int &c, int &d)
{
    int temp;
    temp = c;
    c = d;
    d = temp;
}
void bubble_sort(int b[], int n)
{
    for (int i = n - ; i >= ; --i)
    {
        for (int j = ; j < i; ++j)
        {
            if (b[j] > b[j+])
                swap(b[j], b[j+]);
        }
    }
}

int main()
{
    cout << "請輸入數列" << endl;
int i, k,a[],ans=,key=;
for (i = ; i < ; i++)
    cin >> a[i];

bubble_sort(&a[], );
cout << "排序後的數列為" << endl;
for (i = ; i < ; ++i)
{
    cout << a[i]<<" ";
}

for (k = ; k < ; ++k)
{
    if (a[k] < )
    {
        key = k;
        ans += a[k];
    }

}
if (key == )
cout << "最小子數列和為" << a[] << endl;
else
cout << "最小子數列和為" << ans << endl;

return ;
}
           

Q

如果數列大小不确定

求和：fabonaci數列前20

如題

代碼

//sum.cpp
#include<iostream>
using namespace std;

int main()
{
    int n,m;
    int *pi = new int[];
    pi[] = ;
    pi[] = ;
    cout << pi[] << pi[] << endl;
    for (n= ; n <  ; n++)
    {
        pi[n] = pi[n - ] + pi[n - ];
        cout << pi[n] << endl;
    }
    delete pi;
    cin >> m;
    return ;

}
           

MyArray

動态建立數組

代碼

#include<iostream>
#include<string>
using namespace std;
class MyArray {
public:
    MyArray(int leng);
    ~MyArray();
    void Input();
    void Display(string);
protected:
    int *alist;
    int length;
};
MyArray::MyArray(int leng)
{
    if (leng <= )
    {
        cout << "error length";
        exit();
    }
    alist = new int[leng];
    length = leng;
    if (alist == NULL)
    {
        cout << "assign failure";
        exit();
    }
    cout << "MyArray 類對象已建立。" << endl;
}
MyArray::~MyArray()
{
    delete[] alist;
    cout << "MyArray 類對象被撤銷。" << endl;
}
void MyArray::Display(string str)
{
    int i;
    int *p = alist;
    cout << str << length << " numbers are :";
    for (i = ; i<length; i++, p++)
        cout << *p << " ";
    cout << endl;
}
void MyArray::Input()
{
    cout << "Please input " << length << " numbers :" << endl;
    int i;
    int *p = alist;
    for (i = ; i<length; i++, p++)
        cin >> *p;
}
class SortArray :virtual public MyArray {
public:
    void Sort();
    SortArray(int leng) :MyArray(leng)
    {
        len = leng;
        cout << "SortArray類對象已建立。" << endl;
    }
    virtual~SortArray();
private:
    int len;
    int *sp;
};
SortArray::~SortArray()
{
    cout << "SortArray類對象被撤銷。" << endl;
}
void SortArray::Sort()
{
    int q;
    sp = alist;
    for (int i = ; i<len; i++)
    {
        for (int j = ; j<len - ; j++)
        {
            if (*(sp + j)>*(sp + j + ))
            {
                q = *(sp + j);
                *(sp + j) = *(sp + j + );
                *(sp + j + ) = q;
            }
        }
    }
}

class ReArray :virtual public MyArray {
public:
    void Reverse();

    ReArray(int leng) :MyArray(leng)
    {
        len = leng;
        void Reverse();
        cout << "ReArray類對象已建立。" << endl;
    }
    virtual ~ReArray();
private:
    int len;
    int *bp;
};
ReArray::~ReArray()
{
    cout << "ReArray類對象被撤銷。" << endl;
}
void ReArray::Reverse()
{
    int q;
    bp = alist;

    for (int i = ; i<len / ; i++)
    {
        q = *(bp + i);
        *(bp + i) = *(bp + len - i - );
        *(bp + len - i - ) = q;
    }
}
class Average :virtual public MyArray {
public:
    void Aver();
    Average(int leng) :MyArray(leng)
    {
        len = leng;
        cout << "Average類對象已建立。" << endl;
    }
    virtual ~Average();
private:
    int len;
    int *cp;
};
Average::~Average()
{
    cout << "Average類對象被撤銷。" << endl;
}
void Average::Aver()
{
    double q = ;
    cp = alist;
    for (int i = ; i<len; i++)
    {
        q = q + *cp;
        cp++;
    }
    q = q / len;
    cout << "The average of the " << q << endl;
}
class NewArray :public ReArray, public SortArray, public Average
{
public:
    NewArray(int leng);
    ~NewArray();
};
NewArray::NewArray(int leng) :MyArray(leng), SortArray(leng), ReArray(leng), Average(leng)
{
    cout << "\n新數組正在建立。\n";
}
NewArray::~NewArray()
{
    cout << "\n新數組已被清空。\n";
}
int main()
{
    int leng;
    cout << "How many numbers do you want to enter :";
    cin >> leng;
    NewArray a(leng);
    a.Input();
    a.Display("These ");
    a.Sort();
    a.Display("The sorted ");
    a.Reverse();
    a.Display("After inversion ,the ");
    a.Aver();
    return ;
}
           

noname1

代碼

#include<iostream>
using namespace std;
class Base {
public:
    void setx(int i)
    {
        x = i;
    }
    int getx()
    {
        return x;
    }
public:
    int x;
};
class Derived :public Base {
public:
    void sety(int i)
    {
        y = i;
    }
    int gety()
    {
        return y;
    }
    void show()
    {
        cout << "Base::x=" << x << endl;
    }   //語句1
public:
    int y;
};
int main()
{
    Derived bb;                       //語句2     
    bb.setx();                     //語句3
    bb.sety();                     //語句4
    bb.show();                       //語句5
    cout << "Base::x=" << bb.x << endl;    //語句6
    cout << "Derived::y=" << bb.y << endl;   //語句7
    cout << "Base::x=" << bb.getx() << endl;  //語句8
    cout << "Derived::y=" << bb.gety() << endl;   //語句9
    return ;
}
           

noname2

代碼

#include<iostream>
#include <string>  //必須加這個頭檔案
using namespace std;
class Person{
public:
    void input()
    {
        cout << "Num:";
        cin >> number;
        cout << "Name:";
        cin >> name;
        cout << "Sex:";
        cin >> sex;
        cout << "Age:";
        cin >> age;
    }
    void print()
    {
        cout << "Num:" << number << endl;
        cout << "Name:" << name << endl;
        cout << "Sex:" << sex << endl;
        cout << "Age:" << age << endl;
    }
protected:
    int number,age;
    string name,sex;
};
class Student : public Person{
public:
    void input1()
    {
        cout << "Please enter the student's information:" << endl;
        Person::input();
        cout << "Institute:";
        cin >> department;
        cout << "Score:";
        cin >> score;

    }
    void print1()
    {
        cout << "The student's:" << endl;
        Person::print();
        cout << "Institute:" << department << endl;
        cout << "Score:" << score << endl;
    }
private:
    string department;
    float score;
};
class Teacher : public Person{
public:
    void input2()
    {
        cout << "Please enter the teacher's information:" << endl;
        Person::input();
        cout << "Title:";
        cin >> title;
        cout << "Department:";
        cin >> section;
    }
    void print2()
    {
        cout <<"The teacher's:" << endl;
        Person::print();
        cout << "Title:" << title << endl;
        cout << "Department:" << section << endl;
    }
private:
    string title,section;
};
int main()
{
    Student a;
    Teacher b;
    a.input1();
    b.input2();
    a.print1();
    b.print2();
}