Redefining linear list and its basic operation from the angle of practical application "5" _null

There is a mergelist () function. It's one of the most important functions. It's also the hardest, and by this function, many other functions are called.

Through this procedure, it is also a grasp of the overall view of the program.

Used a lot of pointers. Hope everybody slowly, calm down to see. Or you'll get dizzy by the pointer.

The first time in C to write this program more than 300 lines, debugging is good too laborious.

However, always feel that the use of C in the various modular program design skills Some lack of skill, need guidance. There are related books of hope to recommend.

/* Author:star data:2011.04.09 to redefine the linear list and its basic operation from the practical angle of application * * * #include <iostream> #include <stdio.h> #include <malloc.h> using namespace std; #define ERROR 0 #define OK 1 typedef int ELEMTYPE; typedef int STATUS; typedef struct LNODE {elemtype data; struct Lnode *next;} *link,*position; The typedef struct//linked list Type {link head,tail;//points respectively to the header node in the linear list and the last node int len;} linklist; Status makenode (link &p, Elemtype e) {//Assign a node with P pointing to the value E and return OK, if the allocation fails, return the error P = (link) malloc (sizeof (Lnode)); F (!p) {cout << "allocation node failed!"; return ERROR; else p->data = e; return OK; } void Freenode (Link &p) {//release P refers to node free (p); p = NULL;} Status initlist (linklist &l) {Link p; if (! (Makenode (P,-1)) return ERROR; P->next = NULL; L.head = p; L.tail = p; L.len = 0; return OK; } void Insfirst (linklist &l, link h, link s) {//known H point to Linked header node, insert S-point node after head node s->next = h->next; h->next = s ; L.len + +; if (S->next ==null) L.tail = s; } void Delfirst (LinklisT &l, link h, link &q {//known H points to the head node of the linear list, deletes the first node in the list, and returns if (!) with Q. L.len) {cout << ' List is empty! ' <<endl; return;} q = h->next; H->next = q->next; Q->next = null;//This sentence is critical, because Q->next =null in the Append function will be an error. L.len--; if (h->next = NULL) L.tail = h; } void Append (Linklist &l, link s) {//links a string of nodes referred to by pointer S (to each other as pointers) to the last node//In the list L, and changes the tail pointer of the list L to point to the new node int i = 1; Link p =s; while (P->next) {i++ p = p->next;} L.len = i; L.tail->next = s; L.tail = p; } void Remove (linklist &l, link &q) {//delete the tail node in the list L, and with Q return//change the tail pointer of the list L to point to the new tail node if (L.len = = 0) {cout << "table is empty "<< Endl; Return Link p = l.head; while (P->next!= l.tail) p = P->next; Q = P->next; P->next = NULL; L.tail =p; l.len--; } void Setcurelem (link &p,elemtype e) {//is known to point to a node in the list with E update p->data = e;} Elemtype Getcurelem (Link p) {//Returns the value of the data element in the node referred to by P->data;} int listlength (linklist L) {return l.len;} Status ListeMpty (linklist L) {//null operation if (L.len) return 1; return 0;} Position GetHead (linklist l) {//Return list L Middle head node returns l.head;} Position getlast (linklist L) {return l.tail;} Position Priorlast (linklist L, link p) {//known P points to a node in the linked list L, returns null if (P = = l.head) {cout << The node referred to in P refers to the head knot "<< Endl;" return NULL; Link q = l.head; while (q->next!= p) q = q->next; return q; Position Nextpos (linklist L, link p) {//known P points to a node in the list L, returns the direct successor of P to the node,///If no successor, returns null return P->next;} Status Locatepos (linklist l, int i, link &p) {//return p to indicate the position of node I in the list L and return OK, illegal return error if (I < 0 | | i > listlength ( L) {cout << "wrong" <<endl; return ERROR;} else {int j = 0; p = l.head; while (J < i) {p = p->next ; j + +; } return OK; } void visit (int e) {cout << e << "";} void Listtraverse (Linklist L, Void (*visit) (int)) {//traversal operation Link p = l.head p = P->next; while (p) {visit (P-&G T;data); p = P->next; } cout <&Lt Endl Status Listinsert (linklist &l, int i, elemtype e) {Link h,s; if (!) ( Locatepos (L, I-1, h)) return error;//i value is not valid if (!) ( Makenode (s,e)) return error;//is not divided into storage space Insfirst (L, H, s);//For the list starting from the first node, the I-1 node is its head node. int compare (Elemtype E1, elemtype E2) {return e1-e2;} Status mergelist (linklist &la, linklist &lb, linklist &lc, int (*compare) (Elemtype, Elemtype)) {//known single linked list L The elements of a and LB are arranged in a non descending order//merge LA and lb to get the new single linked list LC,LC elements are also arranged by the value not descending the link ha,hb; Link PA,PB; Link q = (link) malloc (sizeof (Lnode)); int a = 0, b = 0; if (! Initlist (Lc)) return ERROR; Storage space allocation Failed ha = GetHead (La); HB = GetHead (lb);//ha and HB point respectively to LA and Lb head node PA = nextpos (LA, ha); PB = Nextpos (Lb, HB);//pa and Pb point to LA and Lb respectively at the current node while (PA && pb) {a = Getcurelem (PA); b = Getcurelem (PB); if ( Compare (A, B) <= 0)//a <= B {delfirst (la,ha, q); Append (Lc, q); PA = Nextpos (La, ha); } else//a > B {delfirst (Lb, HB, Q); Append (Lc, q); PB = Nextpos (Lb,HB); } if (PA) Append (Lc, PA); else Append (LC,PB); Freenode (HA); Freenode (HB); return OK; int main () {linklist lista; Linklist Listb; Linklist LISTC; int i =0;//the return value of the judgment function is 1 or 0 initlist (lista); Initlist (LISTB); for (int j = 1; J <= 5; j)//insert element {i = Listinsert (Lista, J, J) in Lista; if (i = = 0) {cout << "input Error" <&lt ; Endl Break for (int j = 1; J <= 6; j +) {i = Listinsert (Listb, J, J + 2); if (i = = 0) {cout << "input error" << end L Break }} cout << "List A is:"; Listtraverse (lista, visit); cout << "lista length is" << listlength (lista) <<endl; cout << "Lista tail is:" << lista.tail->data << Endl; cout << "Listb for:"; Listtraverse (LISTB, visit); cout << "Listb length is" << listlength (LISTB) <<endl; cout << "Listb tail is" << listb.tail->data << Endl; Mergelist (Lista, listb, LISTC, compare); cout << "LISTC for:"; Listtraverse (LISTC, visit); cout << "Listb length is:" << listlength (LISTC) <<endl; cout << "Listb tail is:" << listc.tail->data <<endl; System ("pause"); return 0; }

VS2008 compile debugging Pass.