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KwickClips Python · 41 sec · free

Why does undo remove the latest change?

Short answer. Because a stack pops the item that went in last.

How does a stack reverse a word?

Push every character, then pop them out in reverse order.

Remember

Undo pops the last change
Pop letters to reverse

How does undo know your last change? A stack. Undo pops the latest change. Here s holds the letters. Each pop gives the last letter, so r is reversed. Remember two things. Undo pops the last change. Popping letters reverses a word.

This clip is from the full lesson: Stack Implementation Using a List — 6 minutes, with the tables, the quick answers and the whole lesson in text.

Useful for: CBSE Class 12 Computer Science (083)

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