C Single-linked list operation

The head pointer holds the number of linked list elements, the head node begins to hold the data, and the tail node points to null

List.h

#ifndef _list_h#define_list_h#include<stdio.h>#include<stdlib.h>#defineDEBUG 0typedefstructnode{intVal; structNode *Next;} Node; Node* L_malloc ();//Allocating MemoryNode * init ();//InitializevoidShow (Node *list);//show linked list elementsintLsearch_pos (Node *list,intn);//Left SearchintRsearch_pos (Node *list,intn);//Right SearchintFind_val (Node *list,intVal);//Value SearchNode * INSERT (node *list,intPosintn);//inserting NodesNode * DEL_NODE (node *list,intn);//Specify location Delete nodeNode * DEL_VAL (node *list,intVal);//Specify a value to delete a node#endif

List.c

#include"list.h"/************************************* * Allocate memory, retry 1 times when failed *************************************/Node*L_malloc () {Node*p =NULL; intCNT =3;  Do{p= (Node *)malloc(sizeof(Node)); } while(NULL = = P &&--cnt);//try again when you fail    if(0>CNT) {Perror ("malloc"); Exit (-1);//memory allocation failed, exit    }    returnp;}/************************************* * Initialize *************************************/Node*init () {Const intnum =8; intCNT =0; Node*head =NULL; Node*pcur =NULL; Node*pnew =L_malloc (); Head= Pcur = Pnew;//Head->val =0;//head pointer, value record number of linked list elements     for(; CNT < num; cnt++) {pnew=L_malloc (); Pnew->val =CNT; Pcur->next =pnew; Pcur=pnew; Head->val++; } pcur->next =NULL; returnHead; }/************************************* * Show *************************************/voidShow (Node *list) {     while(NULL! =list) {printf ("%d->",list->val); List= list->Next; } printf ("end\n\n");}/************************************* * Start from left to search *************************************/intLsearch_pos (Node *list,intN) {    if(N <1|| n > List->val) {//number of linked list values exceededprintf"exceed length of list\n"); return-1; }     for(intCNT =0; CNT < n; cnt++) {List= list->Next; }    returnList->Val; }/************************************* * Start from right to search *************************************/intRsearch_pos (Node *list,intN) {    if(N <1|| n > list->val) {printf ("exceed length of list\n"); return-1; } Node*pcur = list->next;//define 2 pointers: Current positionNode *ptag = list->next;//Target Location     for(intCNT =0; CNT < n; cnt++) {Pcur= pcur->Next; }                                //interval n between the current position and the target position     while(NULL! = pcur) {//The current position is first moved to the end of the footer, where PTag is the location to searchPcur = pcur->next;//Move 2 pointers at a timePTag = ptag->next;//    }    returnPtag->Val;}/************************************* * Search from left to specified value * has value return position, no value return-1 *************************************/intFind_val (Node *list,intval) {    if(DEBUG) printf ("In find_val:\n"); intCNT =1; intLen = list->Val;  for(; CNT <= Len; cnt++) {List= list->Next; if(DEBUG) printf ("list->val:%d\n",list->val); if(val = = list->val) {            returnCNT; }    }    return-1;}/************************************* * Inserts a new value at the specified position *************************************/Node* Insert (Node *list,intPosintN) {    if(DEBUG) printf ("In insert:\n"); Node*pcur =list; Node*pnew =L_malloc (); Pnew->val =N;  for(intCNT =1; CNT < POS && Pcur->next; cnt++) {//exits at the specified position or at the end of the listPcur = pcur->Next; if(DEBUG) printf ("pcur->val:%d\n",pcur->val); }    if(NULL = = Pcur->next) {//to reach the end of the list, test the empty list or run normalization of negative numbersPnew->next = NULL;//Insert Footer When POS is larger than the linked list lengthPcur->next =pnew; }    Else{pnew->next = pcur->Next; Pcur->next =pnew; } list->val++; returnlist;}/************************************* * Specify location Delete value *************************************/Node* Del_node (Node *list,intN) {    if(N <1|| n > list->val) {printf ("exceed length of list\n"); returnlist; } Node*pcur =NULL; Node*ptag =list;  for(intCNT =0; CNT < n; cnt++) {Pcur=PTag; PTag= ptag->Next; } pcur->next = ptag->Next;  Free(PTag); List->val--; returnlist;}/************************************* * Specify a value to delete a node *************************************/Node* Del_val (Node *list,intval) {    intn =Find_val (List,val); if( -1= = N) {//No value specified, no delete        returnlist; }    returnDel_node (list,n);}

Main.c

#include"list.h"intMain () {Node*list =init ();    Show (list); intnum = Lsearch_pos (list,2 ); printf ("The 2th value is%d\n", num);        Show (list); Num= Rsearch_pos (list,2 ); printf ("The value from right 2th is%d\n", num);        Show (list); Num= Find_val (list,5 ); printf ("The value 5 is in%dth\n", num);    Show (list); List= Del_node (list,1 ); printf ("After delete 1th value,the list is:\n");            Show (list); List= Del_val (list,3 ); printf ("After Delete value 3,the list is:\n");            Show (list); List= Del_val (list, - ); printf ("After Delete value 100,the list is:\n");    Show (list);  for(intCNT =Ten; CNT >0; CNT--) {List=Del_node (list, CNT); printf ("After delete%dth value,the list is:\n", CNT);    Show (list); }     for(intCNT =0; CNT < -; CNT + +) {List= insert (list, cnt%5, Rand ()); printf ("After insert a value at%dth,the list is:\n", CNT);    Show (list); } list= Insert (list,6, About ); printf ("After insert a value at 6th,the list is:\n");        Show (list); List= insert (list,-6, About ); printf ("After insert a value at-6th,the list is:\n"); Show (list);}

C Single-linked list operation