title: Python fibonacci series
body: <p>I wrote a Fibonacci series using Python. Could not figure out why second program is giving wrong answer and first one right when both look same.</p>
  
  <p>Below program gives right answer</p>
  
  <pre><code>def fib(n):
    a,b=0,1
    while b&lt;n:
      print b
      a,b=b,a+b
  
  fib(4)
  1
  1
  2
  3
  </code></pre>
  
  <p>Below program gives wrong answer:</p>
  
  <pre><code>def fib(n):
    a = 0
    b = 1
    while b&lt;n:
      print b
      a = b
      b = a+b
  
  fib(4)
  
  1
  2
  </code></pre>