L3.14: Conclusion

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Week 3 concept checklist

• while loop flow and update logic
• factorial and digit-processing with loops
• for loop with range
• direct iteration without range
• nested loops for patterns and tables
• break, continue, pass
• formatted printing using f-strings

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High-value exam traps

• off-by-one in range boundaries
• wrong step sign in range causing empty output
• missing loop-variable update in while
• continue skipping update and creating infinite loop
• confusing pass with continue
• forgetting 0! = 1
• formatting mismatch: string with numeric format code

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Integrated mixed practice

1. Compute factorial using while.
2. Compute sum of first n numbers using for.
3. Print 3x4 star grid using nested loop.
4. Print odd numbers 1 to 15 using continue.
5. Stop loop at first value divisible by 9 using break.
6. Print table of 6 with alignment:

 6 x  1 =   6
 6 x  2 =  12
...

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Mixed MCQ drill

1. Output?

for i in range(1, 5):
    print(i, end=' ')

2. Output?

i = 1
while i < 4:
    i += 1
print(i)

3. Which keyword skips current iteration only?
4. Which loop is better for iterating over string characters?
5. range(5, 1, -1) gives what values?

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Answers

1. 1 2 3 4
2. 4
3. continue
4. for
5. 5, 4, 3, 2

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Next-step suggestion

• solve 20 output-prediction questions on loops
• write 10 pattern programs from memory
• dry-run at least 5 nested-loop snippets by hand