/

#include <iostream>
#include <stdio.h>
#include <stdlib.h>


using namespace std;


/* Abstract class for all types of lexem*/

class lexeme {
protected:
    lexeme** children;                                      // part of tree of relations
    int beginPos;                                           // number of position in string, that matches beginning of current lexem

public:
    virtual void parse (char* str) = 0;                             // function for parsing string

    virtual int countRes () = 0;

    lexeme() {
        // make union constructor
    }
};


class digit : public lexeme {
private:
    char res;

public:
    void parse (char* str) {

    }

    int countRes () {
        return 0;         // change to atoi(res)
    }

    digit(int _beginPos, char* str) {
        beginPos = _beginPos;
        res = str[beginPos];
        cout << "Read digit: " << res << endl;
    }
};


/* Class for summand. Rule:  */

class summand : public lexeme {
private:
    int index;

public:
    void parse (char* str) {
        cout<< "Summand parsed";
        if (beginPos <= strlen(str) - 1) {
            int currPos = beginPos;
            index = 0;
            while (str[currPos] != '+' && currPos <= (strlen(str) - 1) ) {
                if (str[currPos] != ' ' ) {
                    lexeme *child;
                    child = new digit(currPos, str);
                    children[index] = child;
                    index++;
                }
                currPos++;
            }
        }
    }

    int countRes () {
        int res = 0;
        char* getStr;
        getStr = new char;
        for(int i = 0; i <= index; i++) {
            //getStr = getStr + children[i]->countRes;
        }
        cout << getStr;
        //convert getStr to int and put in res
        return res;
    }

    summand(int _beginPos) {
        beginPos = _beginPos;
        children = new lexeme*;
    }
};


/* Class for expression. Rule: */

class expression : public lexeme {
private:
    int index;

public:
    void parse (char* str) {
        if (beginPos != strlen(str)) {
            int currPos = beginPos;
            index = 0;
            while (currPos <= (strlen(str) - 1)) {
                if (str[currPos] != '+') {
                    lexeme *child;
                    child = new summand(currPos);
                    child->parse(str);
                    children[index] = child;
                    index++;
                    while(str[currPos] != '+' && currPos <= (strlen(str) - 1)){
                        currPos++;
                    }
                } else {
                    currPos++;
                }
            }
        }
    }


    expression(int _beginPos) {
        beginPos = _beginPos;
        children = new lexeme*;
    }                                                       // init of array

    int countRes () {
        int res = 0;
        for(int i = 0; i <= index; i++) {
        //  res = res + children[i]->countRes;
        }
        return res;
    }

    ~expression() {
        // free children
    }
};


int main () {
    char* str;
    str = new char;
    cout << "Enter the string: ";
    gets(str);
    cout << str;
    lexeme *expr = new expression(0);
    expr->parse(str);
    cout << "Answer:" << endl;
    cout << expr->countRes;
    system("pause");
    return 2;
};