Binario a decimal c++

//Antonio VIllanueva Binario -> decimal
#include <iostream>
#include <cmath> //pow
#include <algorithm> //  std::reverse
using namespace std;

class binarioDecimal {
    public:
    binarioDecimal (const string & str):str(str), decimal (0){};

    void conversionDecimal(){//bin->dec
        std::reverse(str.begin(), str.end());
        for (int n= ( str.length() ) ; n>=0 ; n--){
            if (str[n]=='1'){
                cout <<pow(2, n)<<" ==== "<< str[n]<< " , n = "<<n <<endl;
                decimal += pow(2, n);
            }
        }
    }

    int getDecimal (){return decimal;}

    private:
    string str;
    int decimal;
};

int main(int argc, char *argv[])
{
        string s="0000011111";
        binarioDecimal d(s);
        d.conversionDecimal();
        cout << s<<" = "<<d.getDecimal()<< endl;
}