表达式计算实验3

来源：互联网发布：豆瓣fm for windows 编辑：程序博客网时间：2024/05/24 01:47
#include "stdio.h"#include "conio.h"#include "string.h"#include "stdlib.h"#define null 0typedef struct node{     char item[10];     struct node *next;}node;//定义链式堆栈元素类型char sexpression[200],temp[20],opr[20]; typedef struct stack{     node *top;}stack;  //定义链式堆栈类型typedef struct queuenode{     char item[10];     struct queuenode *next;}queuenode;//定义链式队列元素类型typedef struct queue{     queuenode *front;     queuenode *rear;}queue;//定义链式队列类型stack *createstack() //创建一个空堆栈（不带头结点的链栈）{     stack *s=(stack *)malloc(sizeof(stack));     if(s==null) exit(0);     else     s->top=null;     return s;}int stackempty(stack *s) //判断堆栈是否为空{    if(!s)      {          printf("\nStack if not exit!\n");         exit(0);      }   if(s->top==null)     return 1;   else  return 0;} node *makenode(char *item) //创建一个堆栈结点,并使其数据域等于item{    node *pnode;    pnode=(node *)malloc(sizeof(node));    if(!pnode)    exit(0);    else     {        strcpy(pnode->item,item);         pnode->next=null;     }     return pnode;}void push(char *item,stack *s)//压栈{    node *pnode=makenode(item);    pnode->next=s->top;    s->top=pnode;}void pop(char *item,stack *s)//出栈{    node *pnode;    if(!stackempty(s))     {        pnode=s->top;        strcpy(item,pnode->item);        s->top=pnode->next;        free(pnode);     }}void clearstack(stack *s)//清空堆栈{     node *pnode;     while(!stackempty(s))      {         pnode=s->top;         s->top=pnode->next;         free(pnode);      }}int stacksize(stack *s)//计算栈中结点的个数{     int i=0;     node *pnode;     if(!stackempty(s))      {          for(pnode=s->top;!pnode; pnode=pnode->next)          i++;      }     return i;}void stacktop(char *item,stack *s)//取栈顶元素，但不把栈顶元素出栈{      if(!stackempty(s))      {          strcpy(item,s->top->item);      }  }queuenode *makequeuenode(char *item)//创建一个链队列结点，并使其数据域等于item{     queuenode *pnode;     pnode=(queuenode *)malloc(sizeof(queuenode));     if(pnode==null)     exit(0);     else      {          strcpy(pnode->item,item);          pnode->next=null;      }     return pnode; }queue *createqueue() //创建一个空队列，不带头结点{    queue *q=(queue *)malloc(sizeof(queue));    if(q==null)    exit(0);    else     {         q->front=q->rear=null;     }    return q;}int queueempty(queue *q)//判断一个队列是否为空{     if(!q->front)     return 1;     else      return 0;}void queueinsert(char *item,queue *q)//入队{     queuenode *pnode=makequeuenode(item);     if(queueempty(q))     q->front=q->rear=pnode;     else      {           q->rear->next=pnode;            q->rear=pnode;      }}void queuedel(char *item,queue *q)//出队{      queuenode *pnode;      if(queueempty(q))      printf("出队错误，队列为空！\n");      else       {           pnode=q->front;           strcpy(item,pnode->item);           q->front=pnode->next;           free(pnode);       }}int queuesize(queue *q)//求队列长度{    int i=0;    queuenode *pnode;    if(!queueempty(q))      {          for(pnode=q->front;!pnode; pnode=pnode->next)           i++;      }    return i;}void clearqueue(queue *q)//清空队列{      queuenode *pnode;      while(!queueempty(q))        {            pnode=q->front;            q->front=pnode->next;             free(pnode);        } }void queuefront(char *item,queue *q)//取队头元素，但并不出队{     if(!queueempty(q))     {         strcpy(item,q->front->item);     }}void printqueue(queue *q)//输出队列中的元素{      queuenode *pnode;     if(!queueempty(q))       {          printf("\n队列元素：");          pnode=q->front;          while(pnode)            {               printf("%s ,",pnode->item);               pnode=pnode->next;            }       }}void printstack(stack *s)//输出堆栈中的元素{      node *pnode;     if(!stackempty(s))      {         printf("\n堆栈元素：");         pnode=s->top;         while(pnode)           {              printf("%s ,",pnode->item);              pnode=pnode->next;           }      }}int priorty(char opr)//求运算符号优先级{    switch(opr)      {         case '(': return 0;         case '-': return 1;         case '+': return 1;         case '*': return 2;         case '/': return 2;      }}void caculate(queue *q)//计算后缀表达式的数值，要求最初参与运算的数值是整数{     char temp[20],opr[20],num[20];     double fa,fb;     stack *stack_num=null;     stack_num=createstack();     while(!queueempty(q))      {          queuedel(opr,q);          if((opr[0]>='0'&&opr[0]<='9')||(opr[0]=='.'))          push(opr,stack_num);          else           {              pop(num,stack_num);              fb=atof(num);              pop(num,stack_num);              fa=atof(num);              switch(opr[0])                {                    case '+':fa+=fb;break;                    case '-':fa-=fb;break;                    case '*': fa*=fb;break;                    case '/': if(fb==0)                     {                         printf("\n除0出错！");                         exit(0);                     }                else                     {                        fa/=fb;                        break;                    }                }           sprintf(num,"%f",fa);           push(num,stack_num);           }      }     pop(num,stack_num);     printf("\n运算结果是：%s",num);}stack *stack_opr=null;queue *queue_exp=null;void Process(){   int i=0;   int isnum,j;    while(sexpression[i]!='\0')      {         isnum=j=0;          while(sexpression[i]>='0'&&sexpression[i]<='9')           {              isnum=1;temp[j++]=sexpression[i++];           }         if(isnum)           {              temp[j]='\0';queueinsert(temp,queue_exp);           }        else            {             temp[0]=sexpression[i++];             temp[1]='\0';             switch(temp[0])               {                  case '(':push(temp,stack_opr);break;                  case '+':                  case '-':                  case '*':                   case '/': if(!stackempty(stack_opr))                             while(priorty(temp[0])<=priorty(stack_opr->top->item[0]))                              {                                  pop(opr,stack_opr);                                  queueinsert(opr,queue_exp);                                  if(stackempty(stack_opr))                                  break;                              }                            push(temp,stack_opr);                            break;                 case ')': while(stack_opr->top->item[0]!='(')                             {                                  pop(opr,stack_opr);                                   queueinsert(opr,queue_exp);                             }                          pop(opr,stack_opr);                          break;              }          }        printstack(stack_opr);        printqueue(queue_exp);     }} int main(){       int i,j,isnum;        printf("\n请输入待计算的表达式（中缀式）：\n");    gets(sexpression);    printf("%s",sexpression);    stack_opr=createstack();    queue_exp=createqueue();    //i=0;    Process();     /*while(sexpression[i]!='\0')      {         isnum=j=0;          while(sexpression[i]>='0'&&sexpression[i]<='9')           {              isnum=1;temp[j++]=sexpression[i++];           }         if(isnum)           {              temp[j]='\0';queueinsert(temp,queue_exp);           }        else            {             temp[0]=sexpression[i++];             temp[1]='\0';             switch(temp[0])               {                  case '(':push(temp,stack_opr);break;                  case '+':                  case '-':                  case '*':                   case '/': if(!stackempty(stack_opr))                             while(priorty(temp[0])<=priorty(stack_opr->top->item[0]))                              {                                  pop(opr,stack_opr);                                  queueinsert(opr,queue_exp);                                  if(stackempty(stack_opr))                                  break;                              }                            push(temp,stack_opr);                            break;                 case ')': while(stack_opr->top->item[0]!='(')                             {                                  pop(opr,stack_opr);                                   queueinsert(opr,queue_exp);                             }                          pop(opr,stack_opr);                          break;              }          }        printstack(stack_opr);        printqueue(queue_exp);     }*/      while(!stackempty(stack_opr))         {            pop(opr,stack_opr);            queueinsert(opr,queue_exp);        }     caculate(queue_exp);     printstack(stack_opr);     printqueue(queue_exp);     getch();}
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