C language to achieve a single linked list of reverse order and reverse output instances

The reverse output of a single linked list can be divided into two cases. The other is to reverse the list. This article illustrates the two methods with examples. The details are as follows:

1. Output in reverse order

Example code is as follows:

#include<iostream>
#include<stack>
#include<assert.h>
using namespace std;

typedef struct node{
 int data;
 node * next;
}node;

//Add a tail
node * add(int n, node * head){
 node * t = new node;
 t->data = n;
 t->next = NULL;
 if (head == NULL){
  head = t;
 }
 else if (head->next == NULL){
  head->next = t;
 }
 else{
  node * p = head->next;
  while (p->next != NULL){
   p = p->next;
  }
  p->next = t;
 }
 return head;
}

//Order of the output
void print(node * head){
 node * p = head;
 while (p != NULL){
  cout << p->data << " ";
  p = p->next;
 }
 cout << endl;
}

//recursive
void reversePrint(node * p){
 if (p != NULL){
  reversePrint(p->next);
  cout << p->data << " ";
 }
}

//The stack
void reversePrint2(node * head){
 stack<int> s;
 while (head != NULL){
  s.push(head->data);
  head = head->next;
 }

 while (!s.empty()){
  cout << s.top() << " ";
  s.pop();
 }
}

int main(){

 node * head = NULL;
 for (int i = 1; i <= 5; i++){
  head = add(i, head);
 }
  print(head);
  reversePrint(head);
  reversePrint2(head);
 system("pause");
  return 0;
}

Output in reverse order can be done in three ways: recursion, stack, and output in reverse order. The last one I'm going to talk about.

2. Reverse order of single linked list

Example code is as follows:

#include<iostream>
#include<stack>
#include<assert.h>
using namespace std;


typedef struct node{
 int data;
 node * next;
}node;

node * add(int n, node * head){
 node * t = new node;
 t->data = n;
 t->next = NULL;
 if (head == NULL){
  head = t;
 }
 else if (head->next == NULL){
  head->next = t;
 }
 else{
  node * p = head->next;
  while (p->next != NULL){
   p = p->next;
  }
  p->next = t;
 }
 return head;
}

//cycle
node * reverse(node * head){

 if (head == NULL || head->next == NULL){
  return head;
 }

 node * p1 = head;
 node * p2 = head->next;
 node * p3 = NULL; 
 head->next = NULL;

 while (p2 != NULL){
  p3 = p2;
  p2 = p2->next;
  p3->next = p1;
  p1 = p3;
 }
 head = p1;
 return head;
}

void print(node * head){
 node * p = head;
 while (p != NULL){
  cout << p->data << " ";
  p = p->next;
 }
 cout << endl;
}


//recursive
node * reverse2(node * p){
 if (p == NULL || p->next == NULL){
  return p;
 }

 node * newHead = reverse2(p->next);
 p->next->next = p;
 p->next = NULL;
 return newHead;
}


int main(){

 node * head = NULL;
 for (int i = 1; i <= 5; i++){
  head = add(i, head);
 }
 print(head);
 head = reverse(head);
 print(head);
 head = reverse2(head);
 print(head);

 system("pause");
 return 0;
}

There are two ways to reverse the list: loop and recursion. The easiest way for the reader to understand is to draw it on paper.

I hope the examples described in this paper can be helpful to the learning of data structure and algorithm.