第十三週閱讀項目（6）：鏈表類 .

原創

2020-02-22 07:50

代碼：

#include <iostream>
using namespace std;
class Student  //結點類
{
public:
    Student(int n,double s):num(n), score(s), next(NULL) {}
    ~Student()
    {
          if(!next)
            delete next;
        next=NULL;
    }
    Student *next;   //指向下一個結點
    int num;
    double score;
};

class MyList  //鏈表類，其中的成員是學生
{
public:
    MyList() { head=NULL;     }
    MyList(int n,double s); //以Student(n,s)作爲單結點的鏈表
    ~MyList();
    int display();  //輸出鏈表，返回值爲鏈表中的結點數
    void insert(int n,double s);  //插入：將Student(n,s)結點插入鏈表，該結點作爲第一個結點
    void append(int n,double s);  //追加：將Student(n,s)結點插入鏈表，該結點作爲最後一個結點
    void cat(MyList &il); //將鏈表il連接到當前對象的後面
    int length();  //返回鏈表中的結點數（另一種處理，可以將結點數，作爲一個數據成員）
private:
    Student *head;   //鏈表的頭結點
};
//以下爲類成員函數的定義
MyList::MyList(int n,double s)
{
    head=new Student(n,s);
}

MyList::~MyList()
{
    Student *p=head, *q;
    while (p != NULL)
    {
        q = p;
        p = p->next;
        delete q;
    }
    head = NULL;
}

int MyList::display()
{
    if(head==NULL)
    {
        cout<<"empty\n";
        return 0;
    }
    int cnt=0;
    Student *pt=head;
    while(pt)
    {
        ++cnt;
        cout<<pt->num<<", "<<pt->score<<endl;
        pt=pt->next;
    }
    return cnt;
}

void MyList::insert(int n, double s)
{
    Student * pt=new Student(n,s);
    pt->next =head;
    head=pt;
}

void MyList::append(int n,double s)
{
    Student * pt=new Student(n,s);
    if(head==NULL)
        head=pt;
    else
    {
        Student *pts=head;
        Student *pte=pts->next;
        while(pte)
        {
            pts=pte;
            pte=pts->next;
        }
        pts->next=pt;
    }
}

void MyList::cat(MyList& il)
{
    Student *pt=il.head;
    while(pt)
    {
        append(pt->num,pt->score);
        pt=pt->next;
    }
}

int MyList::length()
{
    int cnt=0;
    Student *pt=head;
    while(pt)
    {
        ++cnt;
        pt=pt->next ;
    }
    return cnt;
}
//測試函數
int main()
{
    int n;
    double s;
    MyList head1;
    cout<<"input head1: "<<endl;  //輸入head1鏈表
    for(int i=0; i<3; i++)
    {
        cin>>n>>s;
        head1.insert(n,s);  //通過“插入”的方式
    }
    cout<<"head1: "<<endl; //輸出head1
    head1.display();

    MyList head2(1001,98.4);  //建立head2鏈表
    head2.append(1002,73.5);  //通過“追加”的方式增加結點
    head2.append(1003,92.8);
    head2.append(1004,99.7);
    cout<<"head2: "<<endl;   //輸出head2
    head2.display();

    head2.cat(head1);   //把head1追加到head2後面
    cout<<"length of head2 after cat: "<<head2.length()<<endl;
    cout<<"head2 after cat: "<<endl;   //顯示追加後的結果
    head2.display();
    return 0;
}

運行結果：