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[求助] [數(shù)據(jù)結(jié)構(gòu)/C++]新人求助，表達(dá)式求值程序無(wú)法運(yùn)行

#pragma once
//順序棧類(lèi)定義
template <class T>
class SqStack
{
private:
T *base;//棧底指針
int top;//棧頂
int stacksize;//棧容量
public:
SqStack(int m);//構(gòu)建函數(shù)
~SqStack() { delete[] base; top = 0; stacksize = 0; }//析構(gòu)函數(shù)
void Push(T x);//入棧
T Pop();//出棧
T GetTop();//獲取棧頂元素
int StackEmpty();//測(cè)棧空
void ClearStack();//清空棧
void StackTop();//返回棧頂指針
void StackTranverse();//顯示棧中元素
};
//順序棧類(lèi)實(shí)現(xiàn)
template <class T>
SqStack<T>::SqStack(int m)
{

base = new T[m];
if (base == NULL)
{
cout << "棧創(chuàng)建失敗，退出!" << endl;
exit(1);
}
stacksize = m;
top = -1;
}

template <class T>
void SqStack<T>:

ush(T x)
{
if (top == stacksize - 1) throw "棧滿，無(wú)法入棧";
top++;
base[top] = x;
//cout<<"top："<<top<<endl;
}

template <class T>
T SqStack<T>:

op()
{
T x;
if (top == -1) throw "�？�，不能出棧";
x = base[top--];
//cout<<"top："<<top<<endl;
return x;
}

template <class T>
T SqStack<T>::GetTop()
{
if (top == -1) throw "�？�，棧頂無(wú)元素";
//cout<<"top："<<top<<endl;
return base[top];
}

template <class T>
int SqStack<T>::StackEmpty()
{
if (top == -1)
return 1;
else
return 0;
}

template <class T>
void SqStack<T>::ClearStack()
{
top = -1;
}

template <class T>
void SqStack<T>::StackTop()
{//返回棧頂指針
cout << "棧頂top= " << top;
}

template <class T>
void SqStack<T>::StackTranverse()
{
int i = top;
while (i >= 0)
cout << base[i--] << '\t';
cout << endl;
}
//SqStack.h，堆棧的類(lèi)

//下面是源程序代碼

#include<iostream>
#include"process.h"
#include"stdio.h"
#include<string.h>
#include<stdlib.h>
#include"SqStack.h"
using namespace std;
char pause;

char Precede(char t1,char t2)
{
char f;
switch(t2)
{
   case '+':
   case '-':if(t1=='('||t1=='=')
            f='<';
            else
            f='>';
            break;
   case '*':
   case '/':if(t1=='*'||t1=='/'||t1==')')
            f='>';
            else
            f='<';
            break;
   case '(':if(t1==')')
            {
            cout<<"ERROR1"<<endl;
            exit(0);
            }
            else
            f='<';
            break;
   case ')':switch(t1)
            {
            case '(':f='=';
                     break;
            case '=':cout<<"ERROR2"<<endl;
                     exit(0);
            default: f='>';
            }
            break;
   case '=':switch(t1)
            {
            case '=':f='=';
                     break;
            case '(':cout<<"ERROR2"<<endl;
                     exit(0);
            default: f='>';
            }
}
return f;
}

bool IsOperator(char c)
{
switch(c)
{
   case'+':
   case'-':
   case'*':
   case'/':
   case'(':
   case')':
   case'=':return true;
   default:return false;
}
}

double Operate(double a,char theta,double b)
{
double c;
switch(theta)
{
   case'+':c=a+b;
         break;
   case'-':c=a-b;
         break;
   case'*':c=a*b;
         break;
   case'/':c=a/b;
}
return c;
}

double Val_Exp(char *exp)
{
SqStack<char> OP(20);
SqStack<double>  OD(20);
char theta;
double a,b,d;
char c,x;
char z[6];
int i;
OP.Push('=');
c=*exp++;
x=OP.GetTop();
while(c!='='||x!='=')
{
   if(IsOperator(c))
   switch(Precede(x,c))
   {
      case'<':OP.Push(c);
               c=*exp++;
               break;
      case'=':x=OP.Pop();
               c=*exp++;
               break;
      case'>':theta=OP.Pop();
               b=OD.Pop();
               a=OD.Pop();
               OD.Push(Operate(a,theta,b));
   }
   else if(c>='0'&&c<='9'||c=='.')
   {
   i=0;
   do
   {
      z=c;
      i++;
      c=*exp++;
   }while(c>='0'&&c<='9'||c=='.');
   z='\0';
   d=atof(z);
   OD.Push(d);
   }
   else
   {
   cout<<"ERROR3"<<endl;;
   exit(0);
   }
   x=OP.GetTop();
}
d=OD.GetTop();
return d;
}

void CreatePostExp(char * exp,char * &postexp)
{
char c,x;
int i=0;
SqStack<char> OP(20);
OP.Push('=');
cout<<"exp:"<<exp<<endl;
c=*exp++;
while(c)
{
if((c>='0'&&c<='9')||c=='.')
{
postexp[i++]=c;
c=*exp++;
}
if(IsOperator(c))
{
postexp[i++]=' ';
           x=OP.GetTop();
switch(Precede(x,c))
{
case'<':OP.Push(c);
                     c=*exp++;
                     break;
               case'=':x=OP.Pop();
                     c=*exp++;
                     break;
               case'>':postexp[i++]=OP.Pop();
      break;
}
}
postexp='\0';
}
cout<<"后綴表達(dá)式為:"<<postexp<<endl;
}

double Val_PostExp(char *postexp)
{
int i;
char z[6];
double v=0,d=0,a,b;
char c;
SqStack<double> OD(20);
c=*postexp++;
while(c!='\0')
{
if((c>='0'&&c<='9')||c=='.')
{
i=0;
do
{
z[i++]=c;
c=*postexp++;
}while(c>='0'&&c<='9'||c=='.');
z='\0';
d=atof(z);
OD.Push(d);
}
if(IsOperator(c))
{
b=OD.Pop ();
a=OD.Pop ();
OD.Push (Operate(a,c,b));
c=*postexp++;
}
c=*postexp++;
}
v=OD.Pop ();
return v;
}
void CreatePreFax(char *exp, char *&prefax)
{
char q;
char m[20];
int i, j, k;
i = j = k = 0;
SqStack<char> OP(20);
SqStack<char> OM(20);
SqStack<char> ON(20);
while (*exp != '=')
OM.Push(*exp++);
while (!OM.StackEmpty())
{
q = OM.Pop();
if ((q >= '0'&&q <= '9') || q == '.')
{
m[i++] = q;
}
if (q == ')')
OP.Push(q);
while ((q == '+') || (q == '-') || (q == '*') || (q == '/'))
{
m[i++] = ' ';
if (OP.StackEmpty() || OP.GetTop() == ')' || Precede(q, OP.GetTop()) == '>' || Precede(q, OP.GetTop() )== '=')
{
OP.Push(q);
break;
}
else
m[i++] = OP.Pop();
}
if (q == '(')
{
while (OP.GetTop() != ')')
m[i++] = OP.Pop();
OP.Pop();
}
}
while (!OP.StackEmpty())
{
m[i++] = OP.Pop();
}
m = '\0';
while (m[j] != '\0')
{
ON.Push(m[j++]);
}
while (!ON.StackEmpty())
prefax[k++] = ON.Pop();
prefax[k] = '\0';
cout << "前綴表達(dá)式為:" << prefax << endl;
}

double Val_PreFax(char *prefax)
{
int i, j;
char c;
char z[6];
char s[6];
SqStack<char>OS(20);
SqStack<double>OD(20);
double v = 0, d = 0, a, b;
while (*prefax != '\0')
{
OS.Push(*prefax++);
}
while (!OS.StackEmpty())
{
c = OS.Pop();
if ((c>='0'&&c<='9')||c=='.')
{
i = 0;
do
{
z[i++] = c;
c = OS.Pop();

} while ((c>='0'&&c<='9')||c=='.');
i--;
for (int j = 0; i >= 0; i--)
s[j++] = z;
s = '\0';
d = atof(s);
OD.Push(d);
}
if (IsOperator(c))
{
b = OD.Pop();
a = OD.Pop();
OD.Push(Operate(b,c,a));

}
}
v = OD.Pop();
return v;
}

int main(void)
{
char exp[20]="(2.2+5)+4*(5-3.1)=";
char *postexp;
postexp=new char[20];
*postexp='\0';
char *prefax;
prefax = new char[20];
*prefax = '\0';
double v1, v2;
system("cls";
int choice;
do
{
cout<<"主菜單\n";
cout<<"1-創(chuàng)建表達(dá)式\n";
cout<<"2-表達(dá)式求值\n";
cout<<"3-求后綴表達(dá)式\n";
cout<<"4-后綴表達(dá)式求值\n";
cout<<"5-求前綴表達(dá)式\n";
cout << "6-前綴表達(dá)式求值\n";
cout << "7-顯示表達(dá)式\n";
cout<<"8-退出\n";
cout<<"Enter choice:";
cin>>choice;
switch(choice)
{
case 1:
      cout<<"請(qǐng)輸入表達(dá)式，以=結(jié)束"<<endl;
cin>>exp;
cin.get(pause);
system("pause";
break;
case 2:
v1=Val_Exp(exp) ;
cout<<exp;
cout<<v1<<endl;
cin.get(pause);
system("pause";
break;
case 3:
CreatePostExp(exp,postexp);
cin.get(pause);
system("pause";
break;
case 4:
v1=Val_PostExp(postexp);
cout<<postexp<<"="<<v1<<endl;
cin.get(pause);
system("pause";
break;
case 5:
CreatePreFax(exp, prefax);
cin.get(pause);
system("pause";
break;
case 6:
v2 = Val_PreFax(prefax);
cout << prefax << "=" << v2 << endl;
cin.get(pause);
system("pause";
break;
case 7:
cout<<endl;
cout<<"已創(chuàng)建的表達(dá)式為：";
cout<<exp<<endl;
   CreatePostExp(exp,postexp);
   CreatePreFax(exp,prefax);
      cin.get(pause);
      system("pause"
break;
case 8:
cout<<"退出運(yùn)算"<<endl;
break;
default:
cout<<"Invalid choice\n";
break;
}
}while(choice!=8);
}

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1樓 2017-01-13 11:22:52

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jiangs111

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【答案】應(yīng)助回帖

★ ★
wolfghost: 金幣+2, 積極應(yīng)助獎(jiǎng)勵(lì)~ 2017-03-09 22:53:00

char c, x;
char z[6];
……
do
{
z = c; //這里前面定義的是數(shù)組，報(bào)錯(cuò)“表達(dá)式必須是可修改的左值”，后面也有類(lèi)似的錯(cuò)誤。
i++;

贊一下

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普通

2樓2017-01-13 12:47:32

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