[数据结构与算法分析] 栈的数组实现

前言

栈的实现比较简单，提前声明一个数组作为元素的存储空间即可。不过这就要求代码中有满栈检查，以免发生数组越界。因为现代计算机系统将栈操作作为指令结构的一部分，所以栈可能是仅次于数组的最基本的数据结构。

代码

整体代码比较简单，只需注意TopOfStack这个索引值的用法即可。

.h中的声明：

#ifndef ARRAYSTACK_H_INCLUDED#define ARRAYSTACK_H_INCLUDEDstruct StackRecord;typedef struct StackRecord *Stack;#define ElementType intint IsEmpty(Stack S);int IsFull(Stack S);Stack CreateStack(int MaxElements);void MakeEmpty(Stack S);void Push(ElementType X, Stack S);ElementType Top(Stack S);void Pop(Stack S);ElementType TopAndPop(Stack S);void PrintStack(Stack S);int StackSize(Stack S);#endif // ARRAYSTACK_H_INCLUDED

.c文件实现

#include "ArrayStack.h"#include <stdlib.h>#include <stdio.h>#define EmptyTOS -1 // which means Empty Top Of Stack.#define MinStackSize 3struct StackRecord {  int Capacity;  int TopOfStack; // TOS is a "index" which points to the top  ElementType * Array;};Stack CreateStack(int MaxElements) {  Stack S;  if (MaxElements < MinStackSize) {    printf("Stack size's too small.\n");  } else {    S = malloc(sizeof(Stack));    if (S == NULL)      printf("Out of space!\n");    S->Array = malloc(MaxElements*sizeof(ElementType));    if (S->Array == NULL)      printf("Out of space!\n");    S->Capacity = MaxElements;    MakeEmpty(S);  }  return S;}int IsEmpty(Stack S) {  return S->TopOfStack == EmptyTOS;}int IsFull(Stack S) {  return S->TopOfStack >= (S->Capacity-1);}void MakeEmpty(Stack S) {  S->TopOfStack = EmptyTOS;}void Push(ElementType X, Stack S) {  if (IsFull(S))    printf("Full Stack!\n");  else    S->Array[++S->TopOfStack] = X;}ElementType Top(Stack S) {  if (!IsEmpty(S)) {    return S->Array[S->TopOfStack];  } else {    printf("Empty Stack\n");    return 0;  }}void Pop(Stack S) {  if (IsEmpty(S))    printf("Empty Stack\n");  else    S->TopOfStack--;}ElementType TopAndPop(Stack S) {  if (!IsEmpty(S)) {    return S->Array[S->TopOfStack--];  } else {    printf("Empty Stack\n");    return 0;  }}int main(){  Stack S = CreateStack(100);  for (int i = 20; i <= 60; i++) {    Push(i,S);  }  while (!IsEmpty(S)) {    printf("%d ",TopAndPop(S));  }  printf("\n");  for (int i = 1; i <= 102; i++) {    Push(i,S);  } // should have twice "Full Stack".  return 0;}

测试运行结果