Infinite loop error by using while statement

Question

I want to know that why this is an infinite loop.

The script is as follows:

   x=1;
   while x<5;
     x=2;
     x=x+2;
     if x==4;
       x=x-1;
     end 
   end

Why is it even here? use a pencil and paper and work it out yourself! — Mitch Wheat, Sep 28 '16 at 04:12
I'm somewhat unfamiliar with the syntax but it looks like they're setting x to 2 at every iteration and if x reaches 4 they subtract 1, so obviously x couldn't possibly reach 5. In fact, if I'm reading this right x should contain 3 at the end of every single iteration (correct me if I'm wrong). — EJoshuaS - Stand with Ukraine, Sep 28 '16 at 04:15
Because you always defining x=2 inside while loop, at the end of loop x always will be 3. — Sundar Singh, Sep 28 '16 at 04:15
Can you clarify what you were trying to accomplish in the first place so we can suggest an alternative? — EJoshuaS - Stand with Ukraine, Sep 28 '16 at 04:22

score 0 · Answer 1 · answered Sep 28 '16 at 04:20

Step through this to see why x will always be less than 5:

x=1;
while x<5;
  x=2; // You set x to 2 at the beginning of every single iteration
  x=x+2; // At this point, x == 4
  if x==4; // The "if" is unnecessary - of COURSE x == 4 - how could it possibly be anything else?
    x=x-1; // x now contains 3
  end
end

At the beginning of every iteration, then, x == 2. At the end of the iteration, x == 3.

Infinite loop error by using while statement

1 Answers1