我的STL之旅 MyList

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
//#include<list>
using namespace std;

//only for int use;
/*
class MyList{
    int *my;
    MyList();
    int back();//返回最后一个元素
    int front();//返回第一个元素
    void clear();//清除所有元素
    bool empty();//是否为空
    void insert(int item); //插入元素
    int pop_back();
    int pop_front();
    void push_back(int item);
    void push_front(int item);
    void sort();
};

MyList::MyList()
{
    my=new int[N];
}
*/
//it's a program to packing
//定义结构，单链表
typedef struct MyList{
    int item;
    struct MyList *next;
}MyList,*List;

List head,back;
int *a=new int[];

//从尾部插入
void push_back(int item)
{
    List p=head;
    while(p->next!=NULL){
        p=p->next;
    }
    List q=(List)malloc(sizeof(MyList));
    q->item=item;
    q->next=NULL;
    p->next=q;
    back=q;
}

//从头部插入
void push_front(int item)
{
    List p,q;
    p=head;
    q=p->next;
    List in=(List)malloc(sizeof(MyList));
    in->item=item;
    p->next=in;
    in->next=q;
}

//从尾部弹出
int pop_back()
{
    List p,q;
    q=head;
    p=q->next;
    while(p->next!=NULL){
        q=p;
        p=p->next;
    }
    q->next=NULL;
    back=q;
    int item=p->item;
    free(p);
    return item;
}

//从头部弹出
int pop_front()
{
    List p=head;
    List q=p->next;
    int item=q->item;
    p->next=q->next;
    free(q);
    return item;
}

//移除元素值为item的所有节点
int remove(int item)
{
    List p=head;
    List q=p->next;
    int num=;
    while(q!=NULL){
        if(q->item==item){
            num++;
            p->next=q->next;
            if(p->next==back){
                back=p;
            }
            q=p->next;
        }
        else{
            p=p->next;
            q=p->next;
        }
    }
    return num;
}

//清除所有元素
void clear()
{
    List p=head;
    p=p->next;
    while(p!=NULL){
        List q=p->next;
        int item=p->item;
        free(p);
        p=q;
        cout<<"clear() "<<item<<endl;
    }
    head->next=NULL;
}

//按位置（index）插入item
void insert(int index,int item)
{
    List p;
    p=head;
    List q=p;
    p=p->next;
    int i=;
    while(p!=NULL){
        i++;
        cout<<"i:"<<i<<endl;
        if(i==index){
            List t=(List)malloc(sizeof(MyList));
            t->item=item;
            q->next=t;
            t->next=p;
            break;
        }

        q=p;
        p=p->next;
    }
    if(i!=index)
        cout<<"你输入的数字错误：please reload:"<<endl;
}

//反转list 通过记录每个节点的值，然后重新赋值
//所以会用到clear（）函数 ，及清除原来链表生成新链表
void reverse()
{
    List p=head;
    int i=;
    while(p->next!=NULL){
        p=p->next;
        int item=p->item;
        a[i++]=item;

    }
    clear();
    p=head;
    cout<<i<<endl;
    for(int j=i-;j>=;j--)
    {
        List q=(List)malloc(sizeof(MyList));
        q->item=a[j];
        q->next=NULL;
        p->next=q;
        p=q;
    }
}

//排序list： 通过记录每个节点的值，然后重新对值进行排序
//所以会用到clear（）函数 ，及清除原来链表生成新链表
void sort()
{
    List p=head;
    int i=;
    while(p->next!=NULL){
        p=p->next;
        int item=p->item;
        a[i++]=item;
    }
    clear();
    p=head;
    sort(a,a+i);
    for(int j=;j<i;j++)
    {
        List q=(List)malloc(sizeof(MyList));
        q->item=a[j];
        q->next=NULL;
        p->next=q;
        p=q;
    }
}

//返回list大小
int size()
{
    List p=head;
    int i=;
    while(p->next!=NULL){
        p=p->next;
        i++;
    }
    return i;
}

//判断是否为空
bool isEmpty()
{
    if(head->next==NULL)
         return true;
    return false;
}
//for test use
void print()
{
    List p=head;
    while(p->next!=NULL){
        p=p->next;
        cout<<p->item<<" ";
    }
    cout<<endl;
}

int main()
{
    head=(List)malloc(sizeof(MyList));
    back=(List)malloc(sizeof(MyList));
    head->next=NULL;
    back=head;

    push_front();
    push_front();
    push_back();
    push_back();
    push_back();
    push_back();
    push_front();
    push_front();
    print();
    sort();
    cout<<"after sort()"<<endl;
    print();
    reverse();
    print();
    cout<<"size() "<<size()<<endl;
    insert(,);
    print();
    cout<<"remove() "<<remove()<<endl;
    print();
    cout<<"pop_back() "<<pop_back()<<endl;
    cout<<"pop_front() "<<pop_front()<<endl;
    print();
    clear();
    print();

    return ;
}