OCR A Level H446 Pseudocode Runner

// Bubble sort an array passed by reference
procedure bubbleSort(items:byRef)
  n = items.length
  do
    swapped = false
    for i = 0 to n - 2
      if items[i] > items[i + 1] then
        temp = items[i]
        items[i] = items[i + 1]
        items[i + 1] = temp
        swapped = true
      endif
    next i
    n = n - 1
  until swapped == false
endprocedure

numbers = [29, 3, 17, 8, 42, 1]
bubbleSort(numbers)
for i = 0 to numbers.length - 1
  print(numbers[i])
next i

Output

1
3
8
17
29
42

// Recursive binary search
function binarySearch(items, target, low, high)
  if low > high then
    return -1
  endif
  mid = (low + high) DIV 2
  if items[mid] == target then
    return mid
  elseif items[mid] < target then
    return binarySearch(items, target, mid + 1, high)
  else
    return binarySearch(items, target, low, mid - 1)
  endif
endfunction

values = [2, 5, 9, 14, 20, 31, 47]
print(binarySearch(values, 20, 0, values.length - 1))
print(binarySearch(values, 4, 0, values.length - 1))

Output

4
-1

// Copy passing marks into a new file
reader = openRead("marks.txt")
writer = openWrite("passed.txt")
passed = 0
while NOT reader.endOfFile()
  line = reader.readLine()
  if int(line) >= 40 then
    writer.writeLine(line)
    passed = passed + 1
  endif
endwhile
reader.close()
writer.close()
print(str(passed) + " marks written to passed.txt")

Output

3 marks written to passed.txt

// Nested loops over a 2D array
array grid[3, 3]
for row = 0 to 2
  for col = 0 to 2
    grid[row, col] = (row + 1) * (col + 1)
  next col
next row

for row = 0 to 2
  line = ""
  for col = 0 to 2
    line = line + str(grid[row, col]) + " "
  next col
  print(line)
next row

Output

1 2 3 
2 4 6 
3 6 9