programming

• Errors in algorithms

  • Syntax errors: program can't finish/fail
  • Logical errors: occur when the program finishes but produces the wrong output
• SQL


  • Primary key: unique identifier (no repeat values)
  • SELECT: list the fields to be displayed
  • FROM: identifies the table
  • WHERE: identifies the search criteria
  • AND
  • Record: a row in table (that is collection of fields)
  • Field: column in table
  • Data types: text/alphanumeric, date/time
• Standard methods of solution

  • Linear search, bubble sort, totalling, counting, finding maximum, minimum and average value
• Linear search


  Iterate through elements until match found, then found = true (break iteration loop), else found = false OUTPUT error
• Bubble sort


  n = length of array, repeat 0 TO n-1 times (pass = repeat through every element in array), all pairs of elements compared and swapped (each j increment represent index, moves onto next pair), largest element will bubble up to last, until j = n - i (number of passes) - 1. minus i means ignore swapping last element as its already sorted
• Totalling


  Keeping a running total of values entered into the algorithm e.g totalling a receipt, total = total + score[i]
• Counting


  Keeps track of the number of times an action has been performed
• Finding maximum, minimum and average value

  max = score[1], min = score[1], iterate: if score[i] > max DO max = score[i], avg = total / score
• Dry-run of an algorithm


  Used to follow algorithms and make sure they perform the required task correctly
• different methods to design and construct a solution to a problem

  1. – structure diagrams – flowcharts – pseudocode
• 3) loop

  1. 7.1 Count-controlled (FOR) loops

  2) 7.2 Post-condition (REPEAT) loops

  3) 7.3 Pre-condition (WHILE) loops