Stretch tasks Programming Fundamentals

Round 1: Quiz Blitz

1. A named value that cannot change while the program runs Constants such as VAT_RATE are set once and never change.
2. 2 % is MOD: 17 divided by 5 is 3 remainder 2.
3. 3 // is DIV, integer division: 5 goes into 17 three whole times.
4. Selection Selection uses if, elif and else to pick a path based on a condition.
5. False range(5) gives 0, 1, 2, 3 and 4. range(1, 6) gives 1 to 5.
6. Pass 80 >= 50 is true, so the first branch runs and the rest are skipped. Put the most restrictive test first.
7. A condition-controlled loop A while loop is condition-controlled. A for loop is count-controlled.
8. 12 The inner loop runs 4 times for each of the 3 outer turns: 3 x 4 = 12.
9. Changing the value means editing one line; It cannot be changed by accident A constant also gives a meaningful name to a value, such as VAT_RATE instead of 0.2.
10. Checks whether x is 5 One equals sign assigns. Two compare.
11. True 15 is at least 13 and at most 19, so both parts are true, and AND needs both.
12. number % 2 == 0 An even number leaves no remainder when divided by 2.

Round 2: Quick Fire

1. • A variable's value can change while the program runs
   • A constant's value is fixed once it is set
   Model answer

   A variable is a named location whose value can change while the program runs. A constant is a named value that is fixed once it has been set.

2. • Sequence
   • Selection
   • Iteration
   Model answer

   Sequence, selection and iteration.

3. • A mark of 70 or more also passes the first test
   • So Distinction is never reached: check mark >= 70 first
   Model answer

   Any mark of 70 or more is also true for the first test, mark >= 50, so it prints Pass and the Distinction branch is never reached. The conditions should be swapped, so mark >= 70 is checked first.

4. • MOD gives the remainder: 17 MOD 5 is 2
   • DIV is integer division: 17 DIV 5 is 3
   Model answer

   MOD gives the remainder after division, so 17 MOD 5 is 2. DIV gives the whole number part of a division, so 17 DIV 5 is 3.

Round 3: Big Think

1. • Uses a loop
   • Asks for the password inside the loop
   • Compares the entry with the correct password
   • Shows the message after the loop
   • Sets the password to an empty string before the loop
   Model answer

   The while loop keeps asking until the password matches, then the message is shown after the loop:

   PythonCopy

   password = ""
   while password != "opensesame":
       password = input("Enter the password: ")
   print("Access granted")

2. • Sequence: steps run in order, such as setting the count before the loop
   • Selection: if a mark is 50 or more, it counts as a pass
   • Iteration: a loop repeats five times
   • Each mark is input inside the loop
   • A counter goes up by 1 for each pass
   • The result is output after the loop
   • The input is cast to an integer
   Model answer

   Sequence: the steps run in order, so passes is set to 0 before the loop and the result is shown after the loop. Iteration: the for loop uses range to repeat five times, asking for a mark each time, and the input is cast to an integer. Selection: if the mark is 50 or more, the count of passes goes up by 1.

   PythonCopy

   passes = 0
   for i in range(5):
       mark = int(input("Enter a mark: "))
       if mark >= 50:
           passes = passes + 1
   print("Passes:", passes)

This or That

1. MOD MOD, or % in Python, gives the remainder. DIV gives the whole number part.
2. 1 to 5 range stops one before its end value.
3. totalPrice Meaningful names make code easier to read, and examiners notice.
4. 8 ** is the exponent: 2 to the power 3 is 8.
5. Fully, for every turn of the outer loop The inner loop completes entirely for each single turn of the outer loop.
6. AND OR needs only one of them to be True.
7. It loops forever That is an infinite loop: something inside must change the condition.
8. The most restrictive test Test mark >= 70 before mark >= 50, or high marks never reach their branch.

Memory Match

• A 4 17 % 5: 2
• B 1 17 // 5: 3
• C 2 17 / 5: 3.4
• D 3 2 ** 4: 16
• E 6 7 + 3 * 2: 13
• F 5 len("hello"): 5

Sort It

1. Selection if mark >= 50: An if statement chooses a path: selection.
2. Selection elif and else branches Extra branches are still selection.
3. Selection A switch statement with several cases Choosing one case out of many is selection.
4. Iteration A count-controlled loop Count-controlled loops are one of the two kinds of iteration.
5. Iteration Repeating until the user types quit Repeating is iteration.
6. Sequence Lines run in the order they are written Sequence is the default way code runs.
7. Selection Choosing between two paths based on a condition That is the definition of selection.
8. Sequence Instructions carried out one after another That is the definition of sequence.
9. Sequence Setting total to 0 before adding to it Getting the order right is part of sequence.
10. Sequence Asking for a name, then printing a greeting Two steps in order: sequence.
11. Iteration while password != secret: A while loop repeats until its condition is false.
12. Iteration for i in range(10): A for loop repeats: iteration.