数据结构 -----双链表的创建及其各功能的实现

<prename="code"class="cpp">#ifndef_DCLIST_H
#define_DCLIST_H

#include<iostream>
#include<assert.h>
usingnamespacestd;

typedefintElemType;

typedefstructNode
{
ElemTypedata;
structNode*next;
structNode*prev;
}Node;

typedefstructList
{
Node*first;
Node*last;
size_tsize;
}List;

voidInitList(List*list);
voidpush_back(List*list,ElemTypex);
voidpush_front(List*list,ElemTypex);
voidshow_list(List*list);
boolpop_back(List*list);
boolpop_front(List*list);
Node*find(List*list,ElemTypekey);
booldelete_val(List*list,ElemTypekey);
boolinsert_val(List*list,ElemTypex);
boolresver(List*list);
voiddestroy(List*list);
voidclear(List*list);
boolIsempty(List*list);
boolmodify(List*list,ElemTypex);
boollength(List*list);
voidsort(List*list);
Node*next(List*list,ElemTypex);
Node*prio(List*list,ElemTypex);
#endif

</pre><precode_snippet_id="662381"snippet_file_name="blog_20150510_2_8934957"name="code"class="cpp">#include"DCList.h"

voidInitList(List*list)
{
Node*s=(Node*)malloc(sizeof(Node));
assert(s!=NULL);
list->first=list->last=s;
list->first->prev=list->last;
list->last->next=list->first;
list->size=0;
}

voidpush_back(List*list,ElemTypex)
{
Node*s=(Node*)malloc(sizeof(Node));
assert(s!=NULL);
s->data=x;

s->prev=list->last;
//s->prev=list->first;
list->last->next=s;

list->last=s;
list->last->next=list->first;
list->first->prev=list->last;
list->size++;
}

voidpush_front(List*list,ElemTypex)
{
Node*s=(Node*)malloc(sizeof(Node));
assert(s!=NULL);
s->data=x;

s->prev=list->first;
s->next=list->first->next;
list->first->next=s;
s->next->prev=s;

if(list->size==0)
list->last=s;

list->size++;
}

voidshow_list(List*list)
{
Node*p=list->first->next;
while(p!=list->first)
{
cout<<p->data<<"-->";
p=p->next;
}
cout<<"Over!"<<endl;
}

Node*find(List*list,ElemTypekey)
{
Node*p=list->first->next;
while(p!=list->first&&p->data!=key)
p=p->next;

if(p!=list->first)

returnp;
returnNULL;
}

booldelete_val(List*list,ElemTypekey)
{
Node*q=find(list,key);
if(q==NULL)
returnfalse;

if(q==list->last)
list->last=q->prev;
q->next->prev=q->prev;
q->prev->next=q->next;
free(q);
list->size--;
returntrue;
}

boolinsert_val(List*list,ElemTypex)
{
Node*p=find(list,x);
if(p!=NULL)
returnfalse;

Node*s=(Node*)malloc(sizeof(Node));
assert(s!=NULL);
s->data=x;

p=list->first;
while(p->next!=list->first)
{
if(x<p->next->data)
break;
p=p->next;
}

s->next=p->next;
p->next->prev=s;

s->prev=p;
p->next=s;

if(p==list->last)
{
list->last=s;
}

list->size++;
returntrue;
}

boolresver(List*list)
{
Node*p=list->first->next;
Node*q=p->next;
p->next=list->first;
list->first->prev=p;
list->last=p;

while(q!=list->first)
{
p=q;
q=q->next;

p->next=list->first->next;
p->next->prev=p;
p->prev=list->first;
list->first->next=p;
}
returntrue;
}
voiddestroy(List*list)
{
clear(list);
free(list->first);
list->first=list->last=NULL;
list->size=0;

}
voidclear(List*list)
{
Node*s=list->first->next;
while(s!=list->first)
{
list->first->next=s->next;
free(s);
s=list->first->next;
}
list->last=list->first;
list->size=0;
}
boolpop_back(List*list)
{
if(Isempty(list))
{
cout<<"链表已经为空"<<endl;
returnfalse;

}
Node*s=list->last->prev;
free(list->last);
s->next=list->first;

list->last=s;
list->size--;
returntrue;
}
boolpop_front(List*list)
{
if(Isempty(list))
{
cout<<"链表已经为空"<<endl;
returnfalse;

}
Node*s=list->first->next;
list->first->next=s->next;
s->next->prev=list->first;
if(list->size==1)
{
list->last=list->first;
}
free(s);
list->size--;
returntrue;

}
boolIsempty(List*list)
{
return(list->size==0);
}
boolmodify(List*list,ElemTypex)
{
Node*s=find(list,x);
ElemTypeitem;
if(s!=NULL)
{
cout<<"请输入要替换的数:";
cin>>item;
s->data=item;
returntrue;
}
else
{
cout<<"链表中没有找到你要替换的数"<<endl;
returnfalse;
}
}
boollength(List*list)
{
Node*s=list->first->next;
intp=1;
while(s!=list->last)
{
p++;
s=s->next;
}
if(Isempty(list))
p=0;

cout<<p<<endl;
returntrue;
}
voidsort(List*list)
{
Node*s=list->first->next;
Node*p=s->next;

s->next=list->first;
list->last=s;

while(p!=list->first)
{
s=p;
p=p->next;
insert_val(list,s->data);
free(s);//调用insert_val（list,s->data）会创建结点
}

}
Node*prio(List*list,ElemTypex)
{
Node*s=find(list,x);
if(s!=NULL)
{
if(s==list->first->next)
{
cout<<"没有前驱!"<<endl;
}
else
{
returns->prev;
}
}
else
{
cout<<"没有找到这个数!"<<endl;
returnNULL;
}
}

Node*next(List*list,ElemTypex)
{
Node*s=find(list,x);
if(s!=NULL)
{
if(s==list->last)
{
cout<<"没有后继"<<endl;
}
else
{
returns->next;
}
}
else
{
cout<<"没有找到要查找的数"<<endl;
returnNULL;
}
}

#include"DCList.h"

voidmain()
{
Listmylist;
InitList(&mylist);

intselect=1;
ElemTypeitem;
Node*p=NULL;
intpos;
Node*s;
while(select)
{
cout<<"**********DCList*******************"<<endl;
cout<<"******hello!menu***********"<<endl;
cout<<"*[0]quit_system[1]push_back*"<<endl;
cout<<"*[2]push_front[3]show_seqlist*"<<endl;
cout<<"*[4]pop_back[5]pop_front*"<<endl;
cout<<"*[6]length[7]insert_val*"<<endl;
cout<<"*[8]sort[9]delete_val*"<<endl;
cout<<"*[10]find[11]prio*"<<endl;
cout<<"*[12]modify[13]clear*"<<endl;
cout<<"*[14]destroy[15]next*"<<endl;
cout<<"*[16]resver*"<<endl;
cout<<"******************over**********"<<endl;
cout<<"请选择:>";
cin>>select;
switch(select)
{
case1:
cout<<"请输入要插入的数据(-1结束):>";
while(cin>>item,item!=-1)
{
push_back(&mylist,item);
}
break;
case2:
cout<<"请输入要插入的数据(-1结束):>";
while(cin>>item,item!=-1)
{
push_front(&mylist,item);
}
break;
case3:
show_list(&mylist);
break;
case4:
pop_back(&mylist);
break;
case5:
pop_front(&mylist);
break;
case6:
length(&mylist);
break;
case7:
cout<<"请输入要插入的数据:";
cin>>item;
insert_val(&mylist,item);
break;
case8:
sort(&mylist);
break;
case9:
cout<<"请输入要插删除的值:>";
cin>>item;
delete_val(&mylist,item);
break;
case10:
cout<<"请输入要查找的值:>";
cin>>item;
p=find(&mylist,item);

if(find(&mylist,item)!=NULL)
cout<<"已找到"<<endl;
else
cout<<"未找到:"<<endl;

break;
case11:

cout<<"请输入要查找前驱的数:>";
cin>>item;
s=prio(&mylist,item);
if(s!=NULL)
cout<<"它的前驱是:"<<s->data<<endl;
break;
case12:
cout<<"请输入要修改的值:>";
cin>>item;
modify(&mylist,item);
break;
case13:
clear(&mylist);
break;
case14:
destroy(&mylist);
break;

case15:
cout<<"请输入要查找后继的数:>";
cin>>item;
s=next(&mylist,item);
if(s!=NULL)
cout<<"它的后继是:"<<s->data<<endl;

break;
case16:
resver(&mylist);
break;

default:
break;
}
}

}