栈缓冲法计算数学表达式

问题描述

输入一个字符串（不含括号，只有个位数），输出计算结果

代码

#include 
   
    #include 
    
     #include 
     
      struct ListNode {
    int data; ListNode* Next; ListNode* Last;};struct List {
    ListNode* header; ListNode* trailer; int _size;};void CreateList(List* l)//build the list{
    l->_size = 0; l->header = (ListNode*)malloc(sizeof(ListNode)); l->trailer = (ListNode*)malloc(sizeof(ListNode)); l->header->Next = l->trailer; l->header->Last = NULL; l->trailer->Last = l->header; l->trailer->Next = NULL;}void InsertList(List* l, int e)//空表，在尾节点前插入{
    ListNode* np = (ListNode*)malloc(sizeof(ListNode)); np->data = e; np->Next = l->trailer; np->Last = l->trailer->Last; l->trailer->Last->Next = np; l->trailer->Last = np; l->_size++;}void PushList(List* l, int e)//入栈{
    ListNode* np = (ListNode*)malloc(sizeof(ListNode)); np->data = e; np->Last = l->header; np->Next = l->header->Next; np->Next->Last = np; l->header->Next = np; l->_size++;}int PopList(List* l)//出栈/出队{
    ListNode* now = l->header->Next; int old = now->data; now->Next->Last = now->Last; l->header->Next = now->Next; free(now); l->_size--; return old;}struct cListNode {
    char data; cListNode* Next; cListNode* Last;};struct cList {
    cListNode* header; cListNode* trailer; int _size;};void cCreateList(cList* l)//build the list{
    l->_size = 0; l->header = (cListNode*)malloc(sizeof(cListNode)); l->trailer = (cListNode*)malloc(sizeof(cListNode)); l->header->Next = l->trailer; l->header->Last = NULL; l->trailer->Last = l->header; l->trailer->Next = NULL;}void cInsertList(cList* l, char e)//空表，在尾节点前插入{
    cListNode* np = (cListNode*)malloc(sizeof(cListNode)); np->data = e; np->Next = l->trailer; np->Last = l->trailer->Last; l->trailer->Last->Next = np; l->trailer->Last = np; l->_size++;}void cPushList(cList* l, char e)//入栈{
    cListNode* np = (cListNode*)malloc(sizeof(cListNode)); np->data = e; np->Last = l->header; np->Next = l->header->Next; np->Next->Last = np; l->header->Next = np; l->_size++;}char cPopList(cList* l)//出栈/出队{
    cListNode* now = l->header->Next; char old = now->data; now->Next->Last = now->Last; l->header->Next = now->Next; free(now); l->_size--; return old;}char orderBetween(char top, char s){
    if (((top == '+' || top == '-') && (s == '*' || s == '/'))||((top=='&')&&(s!='&')))  return '<'; else if ((top == '&')&&(s == '&'))  return '='; else   return '>';}int calcu(int op1, char op, int op2){
    if (op == '+')  return op1 + op2; else if (op == '-')  return op1 - op2; else if (op == '*')  return op1*op2; else  return op1 / op2;}int main(){
    cList formula; cCreateList(&formula); while (1) {
     char tmp;  scanf_s("%c", &tmp);  if (tmp != '\n')   cInsertList(&formula, tmp);  else   break; }  cInsertList(&formula, '&'); List opnd;//运算数栈 cList optr;//运算符栈 CreateList(&opnd); cCreateList(&optr); cPushList(&optr, '&'); cListNode* fp = formula.header->Next;  while (optr._size !=0 ) {
     if ('0' <= fp->data&&fp->data <= '9')  {
      PushList(&opnd, (int)fp->data - 48);   fp = fp->Next;  }  else   switch (orderBetween(optr.header->Next->data, fp->data))   {
      case '<': {
       cPushList(&optr, fp->data);    fp = fp->Next;    break;   }   case '=': {
       cPopList(&optr);    fp = fp->Next;    break;    }   case '>': {
       char op = cPopList(&optr);    int popnd2 = PopList(&opnd);    int popnd1 = PopList(&opnd);    PushList(&opnd, calcu(popnd1, op, popnd2));    break;   }   default:exit(-1);   } }  printf_s("%d", PopList(&opnd));}