周总结

5）学习了C++编程，看了一些相关的习题，感觉还好，因为有一定的编程功底，自学起来不算难，今天总结了用结构体和指针建立单向链表，下面是程序：

/*由主程序调用函数，实现链表的建立、输出、删除和插入，在程序中指定需要删除和插入的结点*/
#include<iostream>
using namespace std;
struct student
{
    long num;
    float score;
    student *next;
};
int n;                                              //定义n为全局变量，本文件各个函数均用他 

int main()
{
    student *creat();
    student *del(student *,long);
    student *insert(student *,student *);
    void print(student *);
    student *head,*stu;
    long del_num;
    cout<<"input records:"<<endl;
    head=creat();                                   //返回头指针
    print(head);                                    //输出全部节点
    cout<<endl<<"input the deleted number:";         
    cin>>del_num;                                   //输入要删除的学号 
    while (del_num!=0)
    {head=del(head,del_num);                        //删除后链表的头地址 
    print(head);                                    //输出全部结点 
    cout<<endl<<"input the deleted number:";
    cin>>del_num;                                   //输入要插入的结点 
    }

    cout<<endl<<"input the inserted number:";
    stu=new student;                                //开辟一个新结点 
    cin>>stu->num>>stu->score;
    while (stu->num!=0)                             //当输入序号为0时结束输入 
    {head=insert(head,stu);                         //返回地址 
    print(head);                                    //输出全部结点 
    cout<<endl<<"input the instered number:";
    cin>>stu->num>>stu->score;
    }
    return 0;
}

student *creat(void)                                //建立链表函数 
{student *head;
student *p1,*p2;
n=0;
p1=p2=new student;                                  //开辟一个新单元并使p1,p2指向他 
cin>>p1->num>>p1->score;
head=NULL;
while (p1->num!=0)
{
    n=n+1;
    if (n==1) head=p1;
    else p2->next=p1;
    p2=p1;
    p1=new student;
    cin>>p1->num>>p1->score;
}
p2->next=NULL;
return (head);
}

student *del(student *head,long num)                //删除结点函数 
{student *p1,*p2;
if (head==NULL)                                     //是空表 
{cout<<"list null"<<endl;return(head);}
p1=head;                                            //p1指向第一个结点 
while (num!=p1->num&&p1->next!=NULL)                //若p1指向的不是所要找的结点且后面还有结点 
{p2=p1;p1=p1->next;}                                //p1后移一个结点 
if (num==p1->num)                                   //找到 
{
    if (p1==head) head=p1->next;                    //若p1指向的是首结点，则head指向第二个结点 
    else p2->next=p1->next;
    cout<<"delete:"<<num<<endl;
    n=n-1;
}
else cout<<"cannot find"<<endl;                     //找不到结点 
return (head);
}

student *insert(student *head,student *stud)        //插入结点函数 
{student *p0,*p1,*p2;
p1=head;                                            //p1指向第一个结点 
p0=stud;                                            //指向要插入的结点 
if (head==NULL)                                     //原来的链表是空表 
{
    head=p0;p0->next=NULL;                          //p0指向的结点是头结点 
}
else
{
    while ((p0->num>p1->num)&&(p1->next!=NULL))
    {
        p2=p1;                                      //p2指向刚才的结点， 
        p1=p1->next;                                //p1后裔一个结点 
    }
    if (p0->num<=p1->num)
    {
        if (head==p1) head=p0;                      //查到原来第一个结点之前 
        else p2->next=p0;                           //插到p2指向的结点之后 
        p0->next=p1;
    }
    else
    {p1->next=p0;p0->next=NULL;}                    //插到最后的结点之后 
    n=n+1;                                          //节点数加1 
    return (head);
}
}


void print(student *head)                           //输出链表函数 
{student *p;
cout<<"Now,These"<<n<<"records are:"<<endl;
p=head;
if (head!=NULL)
do
{
    cout<<p->num<<" "<<p->score<<endl;
    p=p->next;
}while (p!=NULL);
}

By Canicula