#include <iostream>
#include <sstream>
#include <exception>

using namespace std;

namespace A7R9PQ{
class Rectangle{
private:
    double a,b;
public:
    class myExc: public exception{
        private:
           string error_string;
        public:
            myExc(double value)
            {
              stringstream sst;
              sst<<"The number "<<value<<" is not posivite.";
              error_string=sst.str();
            }
             virtual const char* what() const throw()
             {
                      return error_string.c_str();
             }
            ~myExc() throw(){}
    };


    Rectangle(double n1, double n2){ setA(n1); setB(n2);}
    void setA(double a){
        try{
        if(a<0)
            throw myExc(a);
        this->a=a;
        }
        catch(exception& e){
            cout<<e.what()<<endl;
        }
        }
    void setB(double b){
        try{
        if(b<0)
            throw myExc(b);
        this->b=b;
        }
        catch(exception& e){
            cout<<e.what()<<endl;
        }
        }
    double getA()const{ return a;}
    double getB()const{ return b;}
};
}

using namespace A7R9PQ;
int main(){

    Rectangle t1=Rectangle(3.5,4.9);
    Rectangle t2=Rectangle(1.4,9.9);
    Rectangle t3=Rectangle(2.2,7.35);
    try{
        t1.setA(-2);
        t2.setA(4.3);
        t3.setA(8.8);
    }
    catch (...)
    {
        cout<<"error\n";
    }
    cout<<"1. tlap: a: "<<t1.getA()<<", b: "<<t1.getB()<<endl;
    cout<<"2. tlap: a: "<<t2.getA()<<", b: "<<t2.getB()<<endl;
    cout<<"3. tlap: a: "<<t3.getA()<<", b: "<<t3.getB()<<endl;
    return 0;
}