//Stack.h
#ifndef _STACK_H_
#define ElementType int
struct Node;
typedef struct Node *PtrToNode;
typedef PtrToNode Stack;struct Node
{ElementType Element;PtrToNode Next;
};int IsEmpty(Stack S);
Stack CreateStack(void);
void MakeEmpty(Stack S);
void Push(ElementType X,Stack S);
void Pop(Stack S);
ElementType Top(Stack S);#endif
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//Stack.c
#include<stdio.h>
#include "Stack.h"
#include<stdlib.h>int IsEmpty(Stack S)
{return S->Next==NULL;
}Stack CreateStack(void)
{Stack S;S=malloc(sizeof(struct Node));if(S==NULL){printf("out of space\n");}S->Next=NULL;return S;
}void MakeEmpty(Stack S)
{if(S==NULL){printf("Must use CreateStack first");}}void Push(ElementType X,Stack S)
{Stack TmpCell;TmpCell=malloc(sizeof(struct Node));if(TmpCell==NULL){printf("out of space\n");}else{TmpCell->Next=S->Next;TmpCell->Element=X;S->Next=TmpCell;}
}void Pop(Stack S)
{PtrToNode TmpCell;if(S==NULL){printf("Empty of stack\n");}else{TmpCell=S->Next;S->Next=TmpCell->Next;free(TmpCell);}
}ElementType Top(Stack S)
{if(S==NULL){printf("Empty of stack\n");return 0;}else{return S->Next->Element;}
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
//main.c
#include<stdio.h>
#include<string.h>
#include "Stack.h"
#define SIZE 50int Str2num(char *a);         //字符串转换为数字（目前只写了整数的转换）
int main(void)
{Stack S;ElementType x;                        //创建空栈 S=CreateStack();char a[SIZE];char b[10];char *d;int i=0;int j=0;printf("请输入后缀表达式：\n");d=gets(a); printf("您输入的是：\n");puts(a);                //打印输入if(d!=NULL){int c=strlen(a);int flag_int=1;int flag_char=1;//printf(" %d ",c);            //测试 for(i=0;i<c;i++){if(a[i]!=' '){if((a[i]>47)&&(a[i]<58)){flag_char=0;flag_int=1;b[j]=a[i];j++;}else if(!(IsEmpty(S) || IsEmpty(S->Next))) {flag_int=0;flag_char=1;int m,n,p;m=Top(S);Pop(S);n=Top(S);Pop(S);if(a[i]==43){p=m+n;Push(p,S);}if(a[i]==45){p=m-n;Push(p,S);}if(a[i]==42){p=m*n;Push(p,S);}if(a[i]==47){p=m/n;Push(p,S);}printf("\n");int s;s=Top(S); //Push(p,S);//printf(" 1_2 % d\n",s);}}else{if((flag_int==1)&&(flag_char==0)){j=0;int dec;                    //字符串转换为数字 dec=Str2num(b);//printf(" 1-1 %d ",dec);            //测试用 Push(dec,S);}}}ElementType q;q=Top(S);Pop(S);printf("后缀表达式的值为：%d\n",q);}}int Str2num(char *a)                 //字符串转数字
{int b=strlen(a);int i;int num=0;int m;int power=1;for(i=0;i<b;i++)                           //测试通过 {m=(a[i]+2)%10;num=(num+m)*10;} num=num/10;return num;
}