Last semester I didn’t grasp the idea of linked list.Here is a review about the basic manipulation of the linked list
#include<iostream>
#include<string>
using namespace std;
int n;
struct num
{
int data;
struct num *next;
};
struct num *create()//create a new linked list
{
struct num *head=new num,*tail;//open new space for head
cout<<"Please input the size of linked list"<<endl;
cin>>n;
cout<<"Please input the element of linked list"<<endl;
cin>>head->data;
head->next=NULL;
tail=head;
for(int i=1;i<n;i++)
{
tail->next=new num;
cin>>tail->next->data;
tail->next->next=NULL;//ensure that when encountered with the end of the problem ,tail->next==NULL
tail=tail->next;
}
return head;
}
void output(num *start)//output a list from begin to end.
{
num *move=start;
while(move)
{
cout<<move->data<<' ';
move=move->next;
}
cout<<endl;
}
num *del(num *start,int x )//delete an element ‘x’ from list.
{
num *ahead,*now=start;
while(true)
{
if(now->data==x)
{
if(now==start)
now=now->next;
else
{
ahead->next=now->next;
}
cout<<"The element "<<x<<" is deleted"<<endl;
delete now ;
break;
}
if(now->next==NULL)
{
now =NULL;
cout<<"no such element"<<endl;
break;
}
ahead=now;
now=now->next;
}
return start;
}
num *insert(num *head,num *newnode)//insert an new element,which is what newnode points to.newnode->data=element.
{
num *move=head;
if(newnode->data<head->data)
{
newnode->next=head;
head=newnode;
return head;
}
while(move->next!=NULL)
{
if(newnode->data<move->next->data)
{
newnode->next=move->next;
move->next=newnode;//如果把这两句颠倒会有很严重的问题！仔细思考
return head;
}
move=move->next;
}
newnode->next=move->next;
move->next=newnode;
return head;
}
int main()
{
num *p=create();
int x;
cout<<"Please input an element which is to be deleted"<<endl;
cin>>x;
num *q=del(p,x);
output(q);
cout<<"Please input an number which is to be added at sequenial order"<<endl;
num *nnode=new num;
cin>>nnode->data;
num *l=insert(p,nnode);
output(l);
return 0;
}
