ONP is working!, C++ (gcc)

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//g++  4.9.3

#include <iostream>
#include <sstream>
#include <vector>
#include <fstream>

struct Operation_ID
{
    constexpr static int
        Add=0,
        Sub=1,
        Multiple=2,
        Divide=3;
};

struct Option
{
    int Type=0;
    Option(){;}
};

struct IntVar : Option
{
    int Value;
    IntVar(int NewValue)
    {
        Type=1;
        Value=NewValue;
    }
};

struct Operation : Option
{
    int ID;
    Operation(int newID)
    {
        Type=2;
        ID=newID;
    }
};

struct CalcMachine
{
    std::vector<Option*> Sketch;
    std::vector<float> Stack;
    std::vector<int> Oprs;
    
    CalcMachine()
    {
        /*
        Sketch.push_back(new IntVar(2));
        Sketch.push_back(new IntVar(2));
        Sketch.push_back(new IntVar(2));
        Sketch.push_back(new Operation(Operation_ID::Multiple));
        Sketch.push_back(new Operation(Operation_ID::Add));
        */
    }
    
    void AddOperation(int ID)
    {
        if(ID!=-1)
        {
            if(!Oprs.size()||Oprs.back()/2<ID/2)
            {
                Oprs.push_back(ID);
            }
            else
            {
                while(Oprs.size() && Oprs.back()>ID)
                {
                    Sketch.push_back(new Operation(Oprs.back()));
                    Oprs.pop_back();
                }
            }
        }
        else
        {            
            while(Oprs.size())
            {
                Sketch.push_back(new Operation(Oprs.back()));
                Oprs.pop_back();
            }
        }
        
        //Sketch.push_back(new Operation(ID));
    }
    
    void AddIntVar(int Value)
    {
        Sketch.push_back(new IntVar(Value));
    }
    
    float Run()
    {
        AddOperation(-1);
        for(size_t i=0; i<Sketch.size(); ++i)
        {
            Option *Obj=Sketch[i];
            switch(Obj->Type)
            {
                case 1:
                    Stack.push_back(static_cast<IntVar*>(Obj)->Value);
                break;
                case 2:
                    int ID=static_cast<Operation*>(Obj)->ID;
                    if(ID==Operation_ID::Add)
                    {
                        float Value=Stack.back();
                        Stack.pop_back();
                        Stack.back()+=Value;
                    }
                    else if(ID==Operation_ID::Sub)
                    {
                        float Value=Stack.back();
                        Stack.pop_back();
                        Stack.back()-=Value;
                    }
                    else if(ID==Operation_ID::Multiple)
                    {
                        float Value=Stack.back();
                        Stack.pop_back();
                        Stack.back()*=Value;
                    }
                    else if(ID==Operation_ID::Divide)
                    {
                        float Value=Stack.back();
                        Stack.pop_back();
                        Stack.back()/=Value;
                    }
                break;
            }
        }
        if(Stack.size()) 
        {
            float Ret=Stack.back();
            Stack.pop_back();
            return Ret;
        }
        else return 0;
    }
    
    void Set(const std::string &Script)
    {
        std::string Text;
        std::stringstream ss;
        ss<<Script;
        while(ss>>Text)
        {
            std::stringstream ss2;
            if(IsNumber(Text))
            {
                ss2<<Text;
                int Value;
                ss2>>Value;
                AddIntVar(Value);
            }
            else
            {
                if(Text=="+") AddOperation(Operation_ID::Add);
                else if(Text=="-") AddOperation(Operation_ID::Sub);
                else if(Text=="*") AddOperation(Operation_ID::Multiple);
                else if(Text=="/") AddOperation(Operation_ID::Divide);
            }
        }
    }
    bool IsNumber(std::string &Text)
    {
        const char *Itr=Text.c_str();
        while(*Itr)
        {
            if(*Itr!='.'&&(*Itr<'0'||*Itr>'9')) return false;
            ++Itr;
        }
        return true;
    }
};

// 2 + 2 * 2

// 2 2 2 * +

// 1 [0] 1 [1] 1 [2] 2 [*] 2 [+]

int main()
{
    CalcMachine CM;
    std::string Script="2 + 4 / 2";
    std::cout<<Script<<" = ";
    CM.Set(Script);
    std::cout<<CM.Run()<<'\n';
}

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Compilation time: 0.52 sec, absolute running time: 0.14 sec, cpu time: 0 sec, memory peak: 3 Mb, absolute service time: 0,66 sec