逆波兰式

//coded by zzy for Compilation principle
//
#include <iostream.h>
#include <string>
#include <cctype>
#include <vector>
#include <stack>
using namespace::std;

/******************************************************************/
// global value
// 操作符优先等级表用一结构体数组表示

struct  S_Oprsymbol
{
    char OprSymbol;
    int level;
}SoperSym[7] = {
    {'#',-1},
    {'(',0},
    {'+',1},
    {'-',1},
    {'*',2},
    {'/',2},
    {')',0},

};

stack<char>  S_OprS;

stack<string> S_result;

//stack<> S_Num;


/******************************************************************/
//判断字符是否为运算符
bool isOperator(char ch)
{
    switch(ch)
    {
    case '(' : return true;break;
    case ')' : return true;break;
    case '+' : return true;break;
    case '-' : return true;break;
    case '*': return true;break;
    case '/' : return true;break;
    case '#' : return true;break;
        //case '**' : return true;break;
    default: return false;break;
    }
}
/******************************************************************/
int GetOprlevel(char OpS)
{
    for (int index = 0; index < 7; index++)
    {
        if (OpS == SoperSym[index].OprSymbol)
        {
            return SoperSym[index].level;
        }
    }
    cout << "can't find this char" << endl;
    return 999;
}

/******************************************************************/
bool precede(char pop, char ch){
    int popI;
    int chI;
    switch(ch){
        case '(' : chI = 0;break;
        case ')' : chI = 0;break;
        case '+' : chI = 1;break;
        case '-' : chI = 1;break;
        case '*' : chI = 2;break;
        case '/' : chI = 2;break;
        case '#' : chI = -1;break;
            //case '**' : return true;break;
        default: break;
    }
    switch(pop){
        case '(' : popI = 0;break;
        case ')' : popI = 0;break;
        case '+' : popI = 1;break;
        case '-' : popI = 1;break;
        case '*' : popI = 2;break;
        case '/' : popI = 2;break;
        case '#' : popI = -1;break;
            //case '**' : return true;break;
        default: break;
    }

    return popI >= chI ? true : false;
}

/******************************************************************/
//change the expression to RPN

void Translate(string str)
{
    S_OprS.push('#');
    string P_str = NULL;
    string s;
    for (int i = 0; i < str.length(); i++)
    {
        if(isOperator(str[i]) == false)
        {
            P_str += str[i];
        }

        else
        {
        //    s = str[i];
            S_result.push(P_str);

            if (GetOprlevel(str[i]) > GetOprlevel(S_OprS.top()) )
            {
                s = str[i];
                S_OprS.push(str[i]);
            }
            else
            {
                while (GetOprlevel(S_OprS.top()) > GetOprlevel(str[i]))
                {
                    s = S_OprS.top();
                    S_result.push(s);
                    S_OprS.pop();
                }
                if (GetOprlevel(S_OprS.top()) == GetOprlevel(str[i]))
                {
                    if (GetOprlevel(S_OprS.top()) == '(' && GetOprlevel(str[i]) == ')')
                    {
                        S_OprS.pop();
                    }
                }

            }

        }

    }
    while (S_result.empty() !=  false)
    {
        cout << S_result.top();
        S_result.pop();
    }
//    return 0 ;
}



/******************************************************************/
// get the result

int  Calculate(string P_str)
{
    return 0;
}
/******************************************************************/
int main(void)
{
    string str,P_str;
    int result;
    cout << "/***********************************/" << endl;
    cout << "please input your expressions" << endl;
    cout << ":";
    cin >> str;
    Translate(str);
//    P_str = Translate(str);
       cout << "the RPN expression is : " << P_str << endl;
//    result = Calculate(P_str);
//    cout << "the result is : " << result << endl;
    return 0;
}