这是关于链表的程序，出现了问题，不知哪出错，请求帮助！ - 编程论坛

lintaoyn2011-04-02 09:05

程序代码：

#include<iostream>
using namespace std;
#define NULL 0
struct student
{
    int num;
    student*next;
};
int n;

int main()
{
    student*creat(void);
    student*insert(student*,student*);
    student*del(student*,int);
    void print(student*);

    student*head;
    student*stu;
    int del_num;
    cout<<"input num:"<<endl;
    head=creat();
    print(head);
    cout<<endl<<"input the inserted record:";
    stu=new student;
    cin>>stu->num;
    while(stu->num!=0)
    {
        head=insert(head,stu);
        print(head);
        cout<<endl<<"input the inserted record:";
        stu=new student;
        cin>>stu->num;
    }
    cout<<endl<<"input the deleted number:";
    cin>>del_num;
    while(del_num!=0)
    {
        head=del(head,del_num);
        print(head);
        cout<<endl<<"input the deleted number:";
        cin>>del_num;
    }
    return 0;
}
/*……………………………………………………主函数………………………………………………………………*/

student*creat(void)
{
    student*head;
    student*p1;
    n=0;
    head = new student;
    head->next = NULL;
    while(cin>>head->num && head->num == 0)
    {
        cout << "不能创建空链表" << endl;
    }

    student*insert(student*,student*);

    p1 = new student;
    p1->next = NULL;
    while(cin>>p1->num && p1->num != 0)
    {
        head  = insert(head,p1);//使creat()出的链表是有序的。
        p1 = new student;
        p1->next = NULL;
    }
    delete p1;//养成好习惯，虽然是个小程序，但是出现内存泄漏总是不好的。
    return(head);
}

student*insert(student*head,student*stud)
{
    student*p0,*p1,*p2;
    p1=head;
    p0=stud;
    p2 = NULL;
    while((p1 != NULL)&&(p0->num>p1->num))
    {
         p2=p1;
         p1=p1->next;
    }
    if(p2 == NULL)//head->num <= strud->num时p2==NULL
    {
        stud->next = head;
        head = stud;
    }
    else
    {//这是怎样在链表中插入一个新节点。要先做保存
        student* temp = p2->next;
        p2->next = stud;
        stud->next = temp;
    }
    return(head);
}

student*del(student*head,int num)
{
    student*p1,*p2;
    p1=head;
    while(num!=p1->num&&p1->next!=NULL)
    {
        p2 = p1;
        p1=p1->next;
    }
    if(num==p1->num)
    {
        if(p1==head)//自己慢慢看
        {
            student* temp = head;
            head = head->next;
            delete temp;
        }
        else
        {
            student* temp = p2->next;
            p2->next=p1->next;
            delete temp;
        }
        cout<<"delete:"<<num<<endl;
    }
    else
        cout<<"It doesn't exist!";
    return(head);
}


void print(student*head)
{
    student*p;
    cout<<"Now these num are:"<<endl;
    p=head;
    while(p!=NULL)//
    {
        cout << p->num << ' ';
        p=p->next;
    }
    cout << endl;
}

排序出问题的一个原因是因为创建出的链表本身并不保证是有序的。我改了，大体没有错误，但是还是有内存泄漏的问题，你自己改改的。