Stretch tasks Programming Fundamentals

Round 1: Quiz Blitz

1. Character A character is one character. A string is a sequence of them.
2. 3 DIV keeps only the whole number part: 2 goes into 7 three times.
3. 1 MOD gives the remainder: 7 is 3 x 2 with 1 left over.
4. 3.5 / is real division, so the answer keeps its fractional part.
5. Adds 1 to count and stores the result back in count Work out the right-hand side, then store it in the name on the left.
6. Each side of OR must be a complete comparison It must be IF grade = 'A' OR grade = 'B'. Examiners set this trap deliberately.
7. True That is their whole point: selection and iteration can then test the result.
8. Pass 80 ≥ 40 is true, so the first branch runs and the rest is skipped. The most restrictive test must come first.
9. n MOD 2 = 0 An even number leaves no remainder when divided by 2.
10. 2 60 goes into 135 twice: 2 whole minutes.
11. FOR i ← 1 TO 5 The number of repeats is known before the loop starts.
12. The value is changed in only one place; The program cannot change it by accident A named constant also makes the code more readable: price vat, not price 0.2.

Round 2: Quick Fire

1. • The same bits could be the integer 65 or the character A
   • The type tells the computer how to interpret the bits
   Model answer

   The same bits could be the integer 65, the character A, or part of a real number. The data type tells the computer how to interpret the bits.

2. • 135 DIV 60 is 2, the whole minutes
   • 135 MOD 60 is 15, the seconds left over
   Model answer

   135 DIV 60 is 2, the whole number of minutes. 135 MOD 60 is 15, the seconds left over. So 135 seconds is 2 minutes 15 seconds.

3. • Count-controlled repeats a number of times known before it starts
   • Condition-controlled repeats until a condition changes, an unknown number of times
   Model answer

   Count-controlled iteration, such as a FOR loop, repeats a number of times known before it starts. Condition-controlled iteration, such as WHILE or REPEAT, repeats until a condition changes, so the number of repeats is unknown.

4. • A mark such as 80 meets both tests
   • The first true test wins, so the most restrictive must come first
   Model answer

   A mark such as 80 meets both tests, and only the first true test runs, so the most restrictive test, 70 or more, must come first, or every passing student gets a Pass.

Round 3: Big Think

1. • Uses a REPEAT or WHILE loop
   • Takes the password with USERINPUT
   • Compares the entry with the stored password
   • Outputs the message after the loop
   Model answer

   AQA pseudo-codeCopy

   REPEAT
       password ← USERINPUT
   UNTIL password = stored
   OUTPUT 'Welcome'

2. • A constant is fixed and cannot change while the program runs
   • A variable's value can change
   • A named constant makes the code more readable
   • If the rate changes, it is edited in one place
   • The program cannot change it by accident
   Model answer

   A constant is fixed when the program is written and cannot be changed while it runs, whereas a variable's value can change. Using a constant such as vat makes the code more readable, because price * vat explains itself. If the rate changes, it is edited in one place rather than everywhere 0.2 appears, and the program cannot change it by accident.

This or That

1. Real It has a fractional part, even though it is zero.
2. String In quotes, 7 is a character string that just looks like a digit.
3. ≠ ← is assignment. ≠ is the relational operator not equal to.
4. 15 MOD gives what is left over: 135 is 2 x 60 with 15 left over.
5. CONSTANT For example, CONSTANT vat ← 0.2.
6. The last digit of n The remainder after dividing by 10 is the units digit.
7. 15 AND needs both comparisons to be true, and 21 is more than 19.
8. A count-controlled FOR loop The number of repeats is known, so a FOR loop is the right choice, and saying why earns the mark.

Memory Match

• A 4 7 / 2: 3.5
• B 1 7 DIV 2: 3
• C 2 7 MOD 2: 1
• D 5 135 DIV 60: 2
• E 6 135 MOD 60: 15
• F 3 2 * 3 + 1: 7

Sort It

1. String A postcode It mixes letters, digits and a space.
2. String An empty string, "" A string can hold no characters at all.
3. Real -0.5 A real can be negative and fractional.
4. Integer -40 A whole number, positive or negative, is an integer.
5. Real 3.14 It has a fractional part.
6. Real A height of 1.75 metres Heights need a fractional part.
7. Integer The number of people in a queue You cannot have half a person.
8. Character One digit character, such as '7' In quotes, '7' is a character, not a number.
9. Integer 2025 A whole number with no fractional part.
10. String "Hello" A sequence of characters is a string.
11. Character A single initial, such as 'J' One character on its own.
12. Character 'K' A single character.