附上代码：

CAP.h  表达式的计算

//CAP.h            表达式的计算   
#pragma once   
enum{NUMBER, OPERATOR, END, UNKNOWN};   
class Token   
{   
public:   
    double value;   
    char opeor;   
    int type;   
    Token(double _value=0,char _opeor='#',int _type=UNKNOWN)   
        :value(_value),opeor(_opeor),type(_type){}   
};   
Token t[20];   
int por(char ch)   
{   
    switch(ch)   
    {   
    case '(':   
    case '#': return 0;   
    case '+':   
    case '-': return 1;   
    case '*':   
    case '/': return 2;   
    default:return -1;   
    }   
}   
  
  
void Ctpostexp(string str,queue<Token>& q)   
{   
        stack<char> s_ch;   
        s_ch.push('#');   
    int i=0,index_t=0,sum=0;   
    char ch=str[i];   
while(i<str.size())   
    {   
        sum=0;   
        ch=str[i];   
        if((ch<='9'&&ch>='0'))   
        {   
            while((ch<='9'&&ch>='0'))   
            {   
                sum=sum*10+ch-'0';   
                ch=str[++i];   
            }   
       
            t[index_t].type=NUMBER;   
            t[index_t].value=sum;   
            q.push(t[index_t]);   
            ++index_t;   
        }   
        else  
        {   
            if(por(str[i])>por(s_ch.top()))   
            {   
                s_ch.push(str[i]);   
            }   
            else if(str[i]=='(')   
            {   
                s_ch.push(str[i]);   
            }   
            else if(str[i]==')')   
            {   
                while(s_ch.top()!='(')   
                {   
                t[index_t].type=OPERATOR;   
                t[index_t].opeor=s_ch.top();   
                q.push(t[index_t]);   
                s_ch.pop();   
                }   
                s_ch.pop();   
            }   
            else if(str[i]=='#')   
            {   
                while(s_ch.top()!='#')   
                {   
                t[index_t].type=OPERATOR;   
                t[index_t].opeor=s_ch.top();   
                q.push(t[index_t]);   
                s_ch.pop();   
                }   
                s_ch.pop();   
            }   
            else if(por(str[i])<=por(s_ch.top()))   
            {   
                t[index_t].type=OPERATOR;   
                t[index_t].opeor=s_ch.top();   
                q.push(t[index_t]);   
                s_ch.pop();   
                s_ch.push(str[i]);   
            }   
            ++i;   
            ++index_t;   
        }   
           
    }   
}   
double Calpostexp(queue<Token>& q)   
{   
    stack<double> s_int;   
    while(!q.empty())   
    {   
        double a=0,b=0;   
        if(q.front().type==NUMBER)   
        {   
            s_int.push(q.front().value);   
            q.pop();   
        }   
        else if(q.front().type==OPERATOR)   
        {   
            char ch_op=q.front().opeor;    
            switch(ch_op)   
            {   
            case '+':    
                    a=s_int.top();   
                    s_int.pop();   
                    b=s_int.top();   
                    s_int.pop();   
                    s_int.push(b+a);   
                    break;   
            case '-':    
                    a=s_int.top();   
                    s_int.pop();   
                    b=s_int.top();   
                    s_int.pop();   
                    s_int.push(b-a);   
                    break;   
            case '*':    
                    a=s_int.top();   
                    s_int.pop();   
                    b=s_int.top();   
                    s_int.pop();   
                    s_int.push(b*a);   
                    break;   
            case '/':    
                    a=s_int.top();   
                    s_int.pop();   
                    b=s_int.top();   
                    s_int.pop();   
                    s_int.push(b/a);   
                    break;   
            default:break;   
                   
            }   
            q.pop();   
        }   
        else    
        {   
            cout<<"error";break;   
        };   
    }   
    double num=s_int.top();   
    return num;   
}  

exp.h       词法分析和语法分析

#pragma once   
#include<iostream>   
#include<fstream>   
#include <stack>   
#include<map>   
#include <queue>   
#include<vector>   
#include <string>   
#include <sstream>   
using namespace std;   
int kk=0;   
int qq=0;//语法分析   
vector<int>synv;   
vector<string>res_prog;   
int expression();   
int term();   
int factor();   
void scanner(string prog,vector<int>& synv,vector<string>& res_prog)   
{   
    int syn=0,cur=0;     
    string token;   
    stringstream ss;   
     int index_token=0;   
        int sum=0;   
string rwtab[6]={"begin","if","then","while","do","end"};   
char ch;   
do  
 {   
            sum=0;   
        index_token=0;   
        ss.str("");   
        token.clear();   
        ch=prog[cur++];   
        while(ch==' ')    
            ch=prog[cur++];   
           
        if((ch<='z'&&ch>='a')||(ch<='Z'&&ch>='A'))   
        {   
            while((ch<='z'&&ch>='a')||(ch<='Z'&&ch>='A')||(ch<='9'&&ch>='0'))   
            {   
                token.push_back(ch);   
                ch=prog[cur++];   
            }   
            --cur;   
            syn=10;   
            for(int i=0;i<6;++i)   
                if(token==rwtab[i])   
                {   
                    syn=i+1;   
                    break;   
                }   
        }   
        else if((ch<='9'&&ch>='0'))   
        {   
            while((ch<='9'&&ch>='0'))   
            {   
                sum=sum*10+ch-'0';   
                ch=prog[cur++];   
            }   
            syn=11;   
            --cur;   
        }   
    else  
        {   
        switch(ch)   
            {   
        case'<':   
                index_token=0;   
                token.push_back(ch);   
                ch=prog[cur++];   
                if(ch=='>')   
                {   
                    syn=21;   
                    token.push_back(ch);   
                }   
                else if(ch=='=')   
                {   
                    syn=22;   
                    token.push_back(ch);   
                }   
                if(ch=='>')   
                {   
                    syn=21;   
                    --cur;   
                }   
                break;   
        case'>':   
                index_token=0;   
                token.push_back(ch);   
                ch=prog[++cur];   
                if(ch=='=')   
                {   
                    syn=24;   
                    token.push_back(ch);   
                }   
                else  
                {   
                    syn=23;   
                    --cur;   
                }   
                break;   
        case':':   
                index_token=0;   
                token.push_back(ch);   
                ch=prog[cur++];   
                if(ch=='=')   
                {   
                    syn=18;   
                    token.push_back(ch);   
                }   
                else  
                {   
                    syn=17;   
                    --cur;   
                }   
                break;   
        case'+': syn=13;   
                token.push_back(ch);   
                 break;   
        case'-': syn=14;   
                token.push_back(ch);   
                 break;   
        case'*': syn=15;   
                token.push_back(ch);   
                 break;   
        case'/': syn=16;   
                token.push_back(ch);   
                 break;   
        case';': syn=26;   
                token.push_back(ch);   
                 break;   
        case'(': syn=27;   
                token.push_back(ch);   
                 break;   
        case')': syn=28;   
                token.push_back(ch);   
                 break;   
        case'#': syn=0;   
                token.push_back(ch);   
                 break;   
        default:syn=-1;   
            }   
        }   
        synv.push_back(syn);   
    switch(syn)   
            {   
            case 11:   
                //printf("(%d,%d)\n",syn,sum);   
                ss<<sum;   
                res_prog.push_back(ss.str());   
                break;//输出（数的二元组）；   
            case -1:printf("error\n");   
                break;   
            default:   
                //printf("(%d,%s)\n",syn,token.c_str());   
                res_prog.push_back(token);   
                break;//输出（关键字begin的二元组）；break;   
            }   
  } while(syn!=0);   
}   
int expression()   
{   
  
    if(term())   
        return 1;   
    while(synv[qq]==13||synv[qq]==14)   
    {   
        ++qq;   
        if(term())   
            return 1;      
    }   
    if(synv[qq]==0&&kk!=1)   
    {   
        //cout<<"sus"<<endl;   
        //fout<<"sus"<<endl;   
    return 0;   
    }   
    else return 1;   
}   
int term()   
{   
    if(factor())   
        return 1;   
    while(synv[qq]==15||synv[qq]==16)   
    {   
        ++qq;   
        if(factor())   
            return 1;   
    }   
    return 0;   
}   
int factor()   
{   
  
    if(synv[qq]==10||synv[qq]==11)   
        ++qq;   
    else if(synv[qq]==27)   
    {   
        ++qq;   
        expression();   
        if(synv[qq]==28)   
            ++qq;   
        else  
        {   
            //printf(") error\n");   
            kk=1;   
        }   
    }   
    else  
    {   
        //printf("factor synax error\n");   
        //fout<<"factor synax error\n";   
        kk=1;   
        return 1;   
    }   
    return 0;   
}  

main
#include "stdafx.h"   
#include"exp.h"   
#include"CAP.h"   
ostringstream oss;   
int ww=0;   
int apend=0;   
void    DelSpace(string& str)   
{   
    char curr = 0;   
    while (curr<str.size())   
    {   
        if(' '==str.at(curr))   
        str.erase(curr,1);   
        else  
        curr++;   
    }   
}   
void  GetExpression(int a[], int n)   
{   
     string token[] = {"+","-","*","/","+(" ,"-(","*(","/(",")+",")-",")*",")/"," "};   
    //string token[] = {"+","-","*","/"," "};   
    //static char token[] = {'+','-',' '};   
  
  oss.str("");   
    oss<<1<<token[a[0]]<<2<<token[a[1]]<<3<<token[a[2]]<<4<<token[a[3]]   
        <<5<<token[a[4]]<<6<<token[a[5]]<<7<<token[a[6]]<<8<<token[a[7]]<<9;  //9577次时出现异样   
       
        string str=oss.str();   
              DelSpace(str);   
        str.append(1,'#');   
        synv.clear();   
        res_prog.clear();   
            qq=0;   
            kk=0;   
    scanner(str,synv,res_prog);   
    ++ww;   
    if(!expression())   
    {   
        queue<Token>q;   
        Ctpostexp(str,q);   
        double result = Calpostexp(q);   
        if (result == 100)   
        {str.erase(str.size()-1,1);   
            cout << str<< '=' << result << endl;   
        //fout << str<< '=' << result << endl;   
        }   
    }   
       
}   
void  DoEnum(int n, int curr, int to[])   
{   
    if (curr == n)   
    {   
        GetExpression(to, n);   
    }   
    else  
    {   
        for (int i = 0; i<13; ++i)   
        {   
            to[curr] = i;   
            DoEnum(n, curr+1, to);   
        }   
    }   
}   
int _tmain(int argc, _TCHAR* argv[])   
{   
    int to[8];   
    DoEnum(8,0,to);   
    return 0;   
}