Computational Thinking and Programming-I Quiz 9

✅ Answer: (a) for loop

A for loop is the natural choice when you already know how many times to repeat something — e.g. iterating a fixed number of times using range(), or once per item in a list.

✅ Answer: (a) To generate a sequence of numbers

range() generates a sequence of numbers — commonly used to control how many times a for loop runs, or to produce a specific numeric pattern.

✅ Answer: (d) All of the above are valid forms

range() is flexible — it accepts 1, 2, or 3 arguments: just a stop value, a start and stop, or a start, stop, and step. All three forms shown are valid Python syntax. (This question is corrected from the original, whose four options included two identical duplicates of the same 3-argument form — leaving no way to answer correctly as originally written.)

✅ Answer: (b) To execute a block of code repeatedly as long as a condition remains true

A while loop keeps repeating its block as long as its condition stays true — ideal when you don’t know in advance exactly how many repetitions will be needed.

✅ Answer: (c) break statement

break exits the loop immediately and completely — no further iterations run at all, and execution jumps to the code right after the loop.

✅ Answer: (d) continue statement

continue stops the current pass through the loop body right where it is, and jumps to the next iteration — unlike break, the loop itself keeps running.

✅ Answer: (b) A loop placed inside another loop

A nested loop is simply a loop written inside the body of another loop — commonly used for tasks like generating 2D patterns or grids, where the outer loop controls rows and the inner loop controls columns.

✅ Answer: (c) A program to generate a star or number pattern (like a triangle)

Pattern-generation programs (printing triangles, pyramids of stars or numbers) are the textbook example of nested for loops — the outer loop handles each row, and the inner loop prints the characters within that row.

✅ Answer: (c) The sum of the series

A summation program accumulates a running total inside the loop (e.g. total += i) and ends up with the sum of the series — as opposed to a product (which would need multiplication) or an average (which needs an extra division step).

✅ Answer: (a) break exits the entire loop immediately; continue skips only the current iteration and moves to the next

break stops the loop completely — no more iterations happen at all. continue just skips whatever’s left in the current iteration and lets the loop carry on to the next one. (This question replaces a self-contradictory one from the original quiz, whose wording — “exit a loop prematurely and move to the next iteration” — actually describes break and continue’s behaviours mixed together, which doesn’t match either statement individually.)

✅ Answer: (b) [2, 4, 6, 8]

Starting at 2, stepping by 2, and stopping before 10 (exclusive), range(2, 10, 2) produces [2, 4, 6, 8].

✅ Answer: (b) 15

This adds up 1 + 2 + 3 + 4 + 5 = 15. range(1, 6) produces 1 through 5 (6 is excluded).

✅ Answer: (b) 120

This multiplies 1 × 2 × 3 × 4 × 5 = 120 — the factorial of 5, computed using a while loop that stops once i passes n.

✅ Answer: (b) *, **, ***

The outer loop runs for i = 0, 1, 2. On each pass, the inner loop adds (i+1) stars, building a growing triangle: *, then **, then *** — a classic nested-loop pattern program.

✅ Answer: (b) 0, 1, 2

while True would normally loop forever, but the break stops it the moment i reaches 3 — so only 0, 1, 2 get printed before the loop exits.

✅ Answer: (b) 1, 3

For every even i (0, 2, 4), continue skips the print() line entirely. Only the odd values actually get printed: 1, 3.

✅ Answer: (b) [5, 4, 3, 2]

With a negative step, range() counts downward: starting at 5, decreasing by 1 each time, and stopping before it reaches 1 (exclusive): [5, 4, 3, 2].

✅ Answer: (d) 12

The outer loop runs 3 times, and for each of those, the inner loop runs 4 times — so the inner body executes 3 × 4 = 12 times in total.

✅ Answer: (b) It creates an infinite loop that never stops on its own

Since the condition True is always true, the loop has no natural way to stop — without a break (or something that eventually makes the condition false), it becomes an infinite loop, and the program will hang until manually interrupted.

✅ Answer: (c) Nested for loops (an outer loop for rows, an inner loop for columns)

Nested for loops are the standard tool for pattern generation — the outer loop controls how many rows to print, and the inner loop controls how many characters go in each row.