链表反转
就直接贴代码了:
#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;
#define NN 1
struct node
{
int value;
node * next;
node(int v = -1, node *nxt = NULL) : value(v),next(nxt){}
};
node* reverse(node * ); //直接使用 node 代表这个结构体
node * make_link();
void display(node *);
int main()
{
node* head = make_link();
display(head);
head = reverse(head);
display(head);
return 0;
}
node* reverse(node *head)
{
node *pre, *cur, *post;
if(!head || !head->next)//空表或者只有一个节点的表不用反转
return head;
pre = head; ///除了头还需要另外两个辅助变量
cur = pre->next;
while(cur)
{
post = cur->next;
cur->next = pre;
pre = cur;
cur = post;
}
head->next = NULL;
return pre;
}
node * make_link()
{
srand(time(NULL));
node *head = new node();
node *cur = head;
for(int i= 0; i < 9; i++)
{
cur->value = rand() % 10;
cur->next = new node();
cur = cur->next;
cur->next = NULL;
}
cur->value = rand() % 10;
return head;
}
void display(node *head)
{
node *cur = head;
int Nodenum = 0;
while(cur)
{
cout << cur->value << " " ;//<< cur->next<<" \n ";
Nodenum++;
cur = cur->next;
}
cout << endl;
#ifdef NN
cout << Nodenum<<endl;
#endif
}