Exam 98-381 All Questions

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Exam 98-381 topic 1 question 6 discussion

Actual exam question from Microsoft's 98-381

Question #: 6
Topic #: 1

DRAG DROP -
You are building a Python program that displays all of the prime numbers from 2 to 100.
How should you complete the code? To answer, drag the appropriate code segments to the correct location. Each code segment may be used once, more than once, or not at all. You may need to drag the split bar between panes or scroll to view content.
NOTE: Each correct selection is worth one point.
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References:
https://docs.python.org/3.1/tutorial/inputoutput.html
https://stackoverflow.com/questions/11619942/print-series-of-prime-numbers-in-python https://www.programiz.com/python-programming/examples/prime-number-intervals

by Vaibhavdhingra24 at June 24, 2020, 1:26 p.m.

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devpool

Highly Voted 4 years, 1 month ago

p=2 while p<=100: is_prime=True for i in range(2, p): if p % i == 0: is_prime=False break if is_prime == True: print(p) p=p+1

upvoted 7 times

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yasminek

Most Recent 4 years, 3 months ago

continue

upvoted 4 times

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Dkadet159958

4 years, 6 months ago

why is_prime = True it needs to be inside while loop, can someone explain please.

upvoted 4 times

PavanKumpatlaAccountTwo

3 years, 5 months ago

The code asks for prime numbers between 2-100. So we use the while loop with "<=" so that the number is less than or equal to 100. After all, we don't want the number to be over 100 do we? And we use the while loop because it will repeatedly check until the condition is true.

upvoted 1 times

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sadako11

4 years, 6 months ago

is_prime is what is called a flag. In our program its main purpose is to control which number to print. In our case only prime numbers when is_prime = True. if is_prime==True: print(p) When is_prime is set to False (when a non prime number is found) then the statement if is_prime==True: print(p) is not executed. is_prime must be located inside the while loop to reset its value for each number. If it is located outside the while loop it will not reset and will get stuck with the same value throughout the complete while loop. When the loop finds a non primal number (is_prime==False) is_prime will be stuck with False for the whole while loop and the code if is_prime==True: print(p) will never be executed.

upvoted 4 times

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cono

4 years, 7 months ago

Would you not use 'continue' rather than 'break' so loop can be repeated?

upvoted 2 times

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gargaditya

4 years, 8 months ago

Perfect answer,be careful with the 'break' statement which breaks the inner for loop the moment a non prime number is detected(after setting is_prime to false) Also note difference between division(/) and remainder after division(%) logic: eg a number like 6 start with 2,test divisibility by 2, 3,4,5 number like 10 start with 2,test divisibility by 2,3,4....9 If anywhere remainder(ie modulo operation->%) is zero ie fully divisble,then mark non prime and break further testing

upvoted 1 times

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Vaibhavdhingra24

4 years, 11 months ago

Can someone explain the indentation??

upvoted 1 times

FuzzyDunlop

4 years, 11 months ago

The indentation represents the literal indentation you would use when writing the python code. The for loop is within the while loop and the break statement is within the if statement.

upvoted 2 times

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Shanmahi

4 years ago

p = 2 while p <= 100: is_prime = True for i in range(2, p): if p % i == 0: is_prime = False break if is_prime: print(p) p = p+1

upvoted 1 times

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