How to generate different random number between 0 and 1 [duplicate]

This question already has an answer here:

• rand() returns same values when called within a single function 5 answers
• srand() — why call it only once? 7 answers

I want to generate random Number every time I call the

   double Rand(){
srand ( time(NULL) );

double number=(double)rand()/((double)RAND_MAX+
return number;
}
cout<<Rand()<<endl;
cout<<Rand()<<endl;
cout<<Rand()<<endl;

the result is same for all of them. However I want them to be different. Could you please Help me??