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← Spin Loop - Intro to Computer Science

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Showing Revision 5 created 05/25/2016 by Udacity Robot.

  1. So, to get a better sense of how timing works,
  2. I've defined a procedure spin loop. Spin loop starts by
  3. initializing the variable i to zero and then it goes
  4. through a loop n times, each time through the loop is
  5. just adds one to i. So that'll run for longer,
  6. we can, by picking the value of n, make it
  7. go through the loop any number of times. So, let's
  8. try that. So I'll try running the loop 1,000 times and
  9. now we get no result, and the time it took is 0.0001 seconds. So, about a tenth
  10. of a millisecond. Let's try it with a
  11. larger number of executions, so now I am going
  12. to increase the number of iterations by ten,
  13. so the value of n's multiplied by ten. And
  14. if we see that now, the time is, is higher, the time is increased to about six
  15. tenths of a millisecond and we can keep increasing
  16. the time, so let's try looping 100,000 times. And
  17. we see if the time increases. And the time
  18. increased by about a factor of ten. Between looping
  19. 10,000 times and looping 100,000 times. And we'll try
  20. one more time. Let's go for a million. If
  21. we go for a million times, now we're up
  22. to 0.05. So, five hundredths of a second, or
  23. 55 milliseconds. To loop a million times. Still pretty fast, right? We're going
  24. through that loop a million times. It's still much less than a second.
  25. What's important is, we can see that well, the time changes depending on
  26. the input. As we increase the input
  27. to spin loop, the time increases accordingly.