C++ :

#include<iostream>
using namespace std;
int main()
{
	double a,b,c,e,f,d;
	cin>>a;
	cin>>b;
	if(a==0||b==0)
	{
		cout<<"error"<<endl;
		return 0;
	}
	c=a+b;
	c=c*2;
	d=a*b;
	cout<<d<<endl<<c<<".00";
	
}

Pascal :

var
  a,b:real;
begin
   readln(a,b);
   if (a>0) and (b>0) then
     begin
       writeln(a*b:0:2);
       writeln((a+b)*2:0:2);
     end
     else
     writeln('error');
     end.