Question

I have a method in a class as follows…

class foo{
   int bar::randomNum10to50(){
      srand (time(NULL));
      int random10to50 = rand()%50+10; 
      return random10to50;
   }
}

However when I call it from main (just to check the output, because i wasn’t getting the behaviour from the program I expected) like so….

foo create;
for (int i=0; i<20;i++){
    cout<<create.randomNum10to50()<<endl;
}

it’s exactly the same number every time it’s run (ie, 9,9,9,9,9,….; next run: 43,43,43,43,…..) I don’t know what is going wrong.
The code runs very quickly so I was thinking that MIGHT be the issue but I don’t see why there wouldn’t be a difference even slightly between the 20 iterations of it. Any thoughts are appreciated! Thanks!

Answer 1

You need to call srand() once, outside of the randomizer function. Otherwise, you re-seed the random number generator each time with the exact same time value, producing the same initial “random” value.