2.线性表-Linked list

fatal.h

#include <stdio.h>
#include <stdlib.h>

#define Error(Str)        FatalError(Str)
#define FatalError(Str)   fprintf(stderr, "%s
", Str), exit(1)

linkedlist.h

typedef int ElementType;

#ifndef _List_H
#define _List_H

struct Node;
typedef struct Node *PtrToNode;
typedef PtrToNode List;
typedef PtrToNode Position;

List MakeEmpty(List L);
int IsEmpty(List L);
int IsLast(Position P, List L);
Position Find(ElementType X, List L);
void Delete(ElementType X, List L);
Position FindPrevious(ElementType X, List L);
void Insert(ElementType X, List L, Position P);
void DeleteList(List L);
Position Header(List L);
Position First(List L);
Position Advance(Position P);
ElementType Retrieve(Position P);

#endif

linkedlist.c

#include "linkedlist.h"
#include <stdlib.h>
#include "fatal.h"

/* Place in the interface file */
struct Node
{
    ElementType Element;
    Position    Next;
};

List MakeEmpty(List L)
{
    if (L != NULL)
        DeleteList(L);
    L = malloc(sizeof(struct Node));
    if (L == NULL)
        FatalError("Out of memory!");
    L->Next = NULL;
    return L;
}

/* Return true if L is empty */
int IsEmpty(List L)
{
    return L->Next == NULL;
}

/* Return true if P is the last position in list L */
/* Parameter L is unused in this implementation */
int IsLast(Position P, List L)
{
    return P->Next == NULL;
}

/* Return Position of X in L; NULL if not found */
Position Find(ElementType X, List L)
{
    Position P;

    P = L->Next;
    while (P != NULL && P->Element != X)
        P = P->Next;

    return P;
}

/* Delete from a list */
/* Cell pointed to by P->Next is wiped out */
/* Assume that the position is legal */
/* Assume use of a header node */
void Delete(ElementType X, List L)
{
    Position P, TmpCell;

    P = FindPrevious(X, L);

    if (!IsLast(P, L))  /* Assumption of header use */
    {                      /* X is found; delete it */
        TmpCell = P->Next;
        P->Next = TmpCell->Next;  /* Bypass deleted cell */
        free(TmpCell);
    }
}

/* If X is not found, then Next field of returned value is NULL */
/* Assumes a header */
Position FindPrevious(ElementType X, List L)
{
    Position P;

    P = L;
    while (P->Next != NULL && P->Next->Element != X)
        P = P->Next;

    return P;
}

/* Insert (after legal position P) */
/* Header implementation assumed */
/* Parameter L is unused in this implementation */
void Insert(ElementType X, List L, Position P)
{
    Position TmpCell;

    TmpCell = malloc(sizeof(struct Node));
    if (TmpCell == NULL)
        FatalError("Out of space!!!");

    TmpCell->Element = X;
    TmpCell->Next = P->Next;
    P->Next = TmpCell;
}

/* Correct DeleteList algorithm */
void DeleteList(List L)
{
    Position P, Tmp;

    P = L->Next;  /* Header assumed */
    L->Next = NULL;
    while (P != NULL)
    {
        Tmp = P->Next;
        free(P);
        P = Tmp;
    }
}

Position Header(List L)
{
    return L;
}

Position First(List L)
{
    return L->Next;
}

Position Advance(Position P)
{
    return P->Next;
}

ElementType Retrieve(Position P)
{
    return P->Element;
}

testlinkedlist.c

#include <stdio.h>
#include "linkedlist.h"

void PrintList(const List L)
{
    Position P = Header(L);

    if (IsEmpty(L))
        printf("Empty list
");
    else
    {
        do
        {
            P = Advance(P);
            printf("%d ", Retrieve(P));
        } while (!IsLast(P, L));
        printf("
");
    }
}

int main()
{
    List L;
    Position P;
    int i;

    L = MakeEmpty(NULL);
    P = Header(L);
    PrintList(L);

    for (i = 0; i < 10; i++)
    {
        Insert(i, L, P);
        PrintList(L);
        P = Advance(P);
    }
    for (i = 0; i < 10; i += 2)
        Delete(i, L);

    for (i = 0; i < 10; i++)
        if (Find(i, L) == NULL)
            printf("Element %d Find fails
", i);

    printf("Finished deletions
");

    PrintList(L);

    DeleteList(L);

    return 0;
}

函数调用关系图（Call graph）