#include <iostream>
#include <string>
#include <vector>

//method: parse the string and create a vector of numbers and operators then iterate that vector to create the value
int main(){
    std::string str_val = "3*5+11+5*20+9*2*4+135";
    std::vector<std::string> expression;
    std::string number_holder;
    int position = 0;
    for (std::string::iterator it=str_val.begin(); it!=str_val.end(); ++it) {
        std::cout << "position: " << position << std::endl;
        position++;

        if(std::isdigit(*it)){
            number_holder.push_back(*it);
            std::cout << "number is: " << number_holder << std::endl;
        }
        else{
            //if the next char is not a number then its an operator

            expression.push_back(number_holder);
            number_holder = "";

            std::cout << "operator is: " << *it << std::endl;
            std::string str(1, *it);
            expression.push_back(str);
        }
    }

    // There will always be a number as the last operand, so lets add it to the expression vector
    std::cout << "number is: " << number_holder << std::endl;
    expression.push_back(number_holder);

    // lets check the expression vector! TODO: delete this code segment, only for debuging


    //Great! Now lets while loop over the expression vector until its size == 1.
    int value = 0;
    //expression.size()>1
    bool complete_multiplication = false;
    while(!complete_multiplication){
        //view current expression
        std::cout << "expression" << std::endl;
        for(std::vector<std::string>::iterator debug_it=expression.begin(); debug_it!=expression.end(); ++debug_it){
            std::cout << *debug_it << std::endl;
        }
        for (unsigned i=0; i<expression.size(); ++i){
            if (expression[i] == "*"){
                expression[i-1] = std::to_string(std::stoi(expression[i-1])*std::stoi(expression[i+1]));
                expression.erase(expression.begin()+i);
                expression.erase(expression.begin()+i);
                break;
            }
            if (i==expression.size()-1) {
                complete_multiplication = true;
                std::cout << "complete multiplication" << std::endl;
            }

        }

        std::cout << "value: " << value << std::endl;
    }
    bool complete_addition = false;
    while(!complete_addition){
        //view current expression
        std::cout << "expression" << std::endl;
        for(std::vector<std::string>::iterator debug_it=expression.begin(); debug_it!=expression.end(); ++debug_it){
            std::cout << *debug_it << std::endl;
        }
        for (unsigned i=0; i<expression.size(); ++i){
            if (expression[i] == "+"){
                expression[i-1] = std::to_string(std::stoi(expression[i-1])+std::stoi(expression[i+1]));
                expression.erase(expression.begin()+i);
                expression.erase(expression.begin()+i);
                break;
            }
            if (i==expression.size()-1) {
                complete_addition = true;
                std::cout << "complete addition" << std::endl;
            }

        }

    }

    return 0;
}