How Do You Demonstrate Bubble Sorts Algorithm?
• Explain that an algorithm was a “recipe”, a series of steps to solve a problem. • Randomly place 5 cards on a desk and ask the pupil to sort it. • The pupil will sort the cards • Ask the pupil how to verify the sort, perhaps by comparing each pair of cards to validate the invariant “the card on the left is less than or equal to the card on the right” • Next, discuss one of the steps — the swap of adjacent cards. • Discuss how algorithms are simpler when they consider only a few elements at a time, instead of trying to shuffle the entire list at once. • Introduce a flag variable using a coin, or a post-it note. The flag was “set” whenever a swap occurred during a pass. • Introduce the concept of a “pass” over all pairs of adjacent cards. • Initialize the flag to false (e.g., coin beside post-it-note) at the start of a pass over all the cards. • Examine the first pair of cards. If in order, move to the next pair. If not in order, swap the cards and set the flag (move coin onto post-it
