表达式求值

char *base;
char *top;
int stacksize;
}trSqStack;
typedef struct ndSqStack{ //double型操作数栈
double *base;
double *top;
int stacksize;
}ndSqStack;
return 0;
}
double operate(double number1,char op,double number2) //计算
{
double value;
switch(op)
{
case '+':
value=number1+number2;
break;
ndSqStack ndInitStack(ndSqStack S); //构造空栈(操作数)
trSqStack trDestroyStack(trSqStack S); //销毁栈(运算符)
ndSqStack ndDestroyStack(ndSqStack S); //销毁栈(操作数)
OPND.base=NULL; //OPND栈用于存放运算数
OPND.top=NULL;
OPND.stacksize=0;
OPTR=trInitStack(OPTR);
OPTR=operatorPush(OPTR,'#');
OPND=ndInitStack(OPND);
element=evaExp[i];
trSqStack operatorPush(trSqStack S,char element); //插入新的栈顶元素(运算符)
ndSqStack numberPush(ndSqStack S,double element); //插入新的栈顶元素(操作数)
char operatorGetTop(trSqStack S); //返回栈顶元素(运算符)
}
//printf("value is %f",value);
return value;
}
trSqStack trInitStack(trSqStack S) //构造空栈(运算数)
{
S.base=(char*)malloc(STACK_MAXNUM*sizeof(char));
case 3: //'>'
op=operatorGetTop(OPTR); //返回栈顶元素(运算符)
OPTR=operatorPop(OPTR); //删除栈顶元素(运算符)
a=numberGetTop(OPND); //返回栈顶元素(操作数)
double numberLogged(char evaExp[]/*,int i*/); //表达式中关于数字的录入
double operate(double number1,char op,double number2); //计算
int main()
{
char reply;
OPND=numberPop(OPND); //删除栈顶元素(操作数)
b=numberGetTop(OPND); //返回栈顶元素(操作数)
OPND=numberPop(OPND); //删除栈顶元素(操作数)
value=operate(b,op,a);
Hale Waihona Puke break; default:
printf("表达式错误\n");
}
return value;
}
trSqStack operatorPop(trSqStack S) //删除栈顶元素(运算符)
{
char e;
if((S.base==NULL)||(S.base==S.top))
OPND=numberPush(OPND,value); //插入新的栈顶元素(操作数)
i=i-1;
break;
case -1: //错误
printf("表达式错误\n");
return -1;
break;
default:
if(!S.base)
{
printf("内存不足\n");
exit(0);
}
//程序功能：表达式求值且以'#'结束
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <math.h>
#define STACK_MAXNUM 20
#define MAX 20
typedef struct trSqStack{ //char型运算符栈
char evaExp[MAX];
do
{
i=0;
printf("输入表达式且以'#'结束：");
scanf("%s",evaExp);
EvaluateExpression(evaExp);
printf("再次计算输入Y,退出请输入N\n");
printf("是否再次计算：");
e=evaExp[i]-48; //'0'的十进制ASCII码值为48
if(e==(-2)) //-2即小数点'.'
{
if(j==0)
j=i;
else
{
printf("表达式错误，小数点错误\n"); //如“123.3.3”
//printf("element is %c\n",element);
pj=PriorityJudge((operatorGetTop(OPTR)),element);
//printf("pj is %d\n",pj);
switch(pj)
{
scanf(" %c",&reply);
}while(reply=='y'||reply=='Y');
return 0;
}
int EvaluateExpression(char evaExp[]) //表达式求解
{
char element,op;
int pj; //pj即PriorityJudge
{
int e;
int j=0,n; //n==sum
double value;
e=evaExp[i];
while(!isdigit(e)){
i++;
e=evaExp[i];
}
n=0;
while(isdigit(e)||e=='.'){
case 1: //'<'
OPTR=operatorPush(OPTR,element);
break;
case 2: //'='
OPTR=operatorPop(OPTR); //删除栈顶元素(运算符)
break;
double a,b,number,value;
trSqStack OPTR;
ndSqStack OPND; //栈的定义
OPTR.base=NULL; //栈初始化
OPTR.top=NULL; //OPTR栈用于存放运算符
OPTR.stacksize=0;
printf("出错\n");
else
{
e=*(--S.top);
// printf("已删除栈顶元素%d\n",e);
}
return S;
}
ndSqStack numberPop(ndSqStack S) //删除栈顶元素(操作数)
{
double e;
}
}
else if((element=='+')||(element=='-')||(element=='*')||(element=='/')||(element=='(')||(element==')')||(element=='#'))
{
//printf("进入while-else if\n");
if(number==(-1))
return -1;
else
{
//printf("number is %f",number);
OPND=numberPush(OPND,number); //插入新的栈顶元素(操作数)
//printf("while-if numberPush 插入成功\n");
while((element!='#')||((operatorGetTop(OPTR))!='#')){
if(((element>='0')&&(element<='9'))||(element=='.'))
{
//printf("进入while-if\n");