鏈表“逆置”的2種方法

 

#include <iostream>
using namespace std;


struct list
{
    int data;
    list *next;
};
 list *head=new list;
 list *tail=head;

 void add(int n)
 {
     list *p=new list;
     memset(p,0,sizeof(list));
    tail->next=p;
    p->data=n;
    tail=p;
 }
 void print()
 {
     list *p=head->next;
     while(p)
     {
         cout<<p->data<<endl;
         p=p->next;
     }
 }
 void printtail()
 {
     list *p=tail;
     while(p->next)
     {
         cout<<p->data<<endl;
         p=p->next;
     }
 }
 void nizhi1()
 {
    int sum=0;
    list *p=head->next;
    while(p){p=p->next;sum++;}

    for (int i=0;i<sum/2;i++)
    {
        p=head->next;
        for (int j=0;j<i;j++ )  //j<i
        {
            p=p->next;

        }
        cout<<"l:"<<p->data<<endl;
        list *r=head->next;
        for (int jj=0;jj<sum-i-1;jj++)  //-1
        {
            r=r->next;
        }
            cout<<"r:"<<r->data<<endl;
        int temp=p->data;
        p->data=r->data;
        r->data=temp;
    }
    }
void nizhi2()
{
int sum =0;      //新建一個動態數組存放鏈表地址 address[0]存放head地址
list *p=head;
while(p) {sum++;p=p->next;}
list  **address=new list *[sum];
memset(address,0,sizeof(address));
p=head;
for (int i=0;i<sum;i++)
{
    address[i]=p;
    p=p->next;
}

cout<<"sum:"<<sum<<endl;
p=head;
p->next=0;
for (i=1;i<sum;i++)
{
    address[i]->next=address[i-1];
}

 delete [] address;

}

int main()
{
add(1);
add(2);
add(3);
add(4);
add(5);
print();
cout<<endl;
nizhi1();
print();
nizhi2();
cout<<endl;
printtail();
return 0;
}