data structures

• • arrays are lists of values that are grouped together
  • in an array, all items should be the same data type
• data types

  • string – any amount of text (letters, numbers and symbols)
  • integer – a whole number
  • real – a number with a part after the decimal point
  • character – one single ‘character’ of a string i.e. a letter, number, symbol
  • boolean – True or False
• pseudocode for length of a string

  LEN(String)
• pseudocode for character position


  POSITION(String, Char)
• pseudocode for substring

  SUBSTRING(FirstPosition, LastPosition, String)
• pseudocode for concatenation

  String1 + String2
• pseudocode for encoding characters

  CHAR_TO_CODE(Character)
• pseudocode for decoding characters

  CODE_TO_CHAR(Integer)
• pseudocode for converting string to integer

  STRING_TO_INT(String)
• pseudocode for converting string to real

  STRING_TO_REAL(String)
• pseudocode for converting integer to string

  INT_TO_STRING(Integer)
• pseudocode for converting realto string

  REAL_TO_STRING(Real)
• a record

  • similar to an array but all of the items don’t need to be the same type
  • individual data items within a record are known as fields
  • instead of accessing the data using the index, we would access it using the field name instead