به انگلیسی

One pass, one running answer

Computing · Programming · ages 15-16

Name ______________________ Date ____________

You are about to loop through a list and count the items that pass a test. What should the counter start at before the loop?
- 0
- 1
- The first item in the list
- The number of items in the list
A program loops through the list [5, 9, 3, 11] and keeps a running total, starting at 0. What is the total after the loop finishes?
Answer: ______________
Before totalling a list, what should the running total start at?
- 0
- 1
- The last item
A counting loop adds 1 only when an item passes the test.
Circle one: True False
A loop counts how many items in the list [4, -7, 0, -2, 6, -5, -1] are negative, starting the counter at 0. What is the counter after the loop finishes?
- 3
- 4
- 5
- 6
In the list [3, 8, 15, 22, 6, 19], how many numbers are greater than 10?
Answer: ______________
A loop adds up every number in the list [15, 3, 8, 12, 5], starting the running total at 0. What is the final total?
Answer: ______________
Find the largest of 12, 45, 7, 39, 45 and 3 by checking each once.
Answer: ______________
A friend starts best-so-far at 0 for -8, -2, -15 and -4. What will the loop claim?
- -2, the true largest
- -15, the smallest
- 0, which sits in no slot
A loop sums the numbers in the list [2, 4, 6, 8, 10, 12], starting the running total at 0. What is the final total?
Answer: ______________

Answer key

For grown-ups. Fold this page away before handing over the rest.

0 · Before any item is checked, nothing has passed yet, so the counter starts at 0 and adds 1 per pass.
28 · Adding each number to the total one at a time gives you the full sum by the end of the loop.
0 · Starting at 0 leaves the total unchanged until the first real item joins.
True · The counter moves for passes and stays put for the rest.
4 · Only -7, -2, -5 and -1 pass the negative test. 0 is not negative, so the counter increases four times.
3 · Checking each number against the rule one at a time tells you how many pass.
43 · Each number gets folded into the total in order, so the last value you see is the full sum.
45 · Carrying the best seen so far ends the walk at 45.
0, which sits in no slot · Every item falls below 0, so nothing ever replaces the start value.
42 · Adding each number in order builds the total step by step until every item has been included.