2. Software Development, Computing Higher, Revision

Parameters and data flow

This is always a hot topic at this time of year. It’s been a while since we did procedures, parameters, byVal, Byref & Data Flow

From Shawlands Acc

  • Data flow within a program is handled by parameters
  • A parameter is a value or a variable which is passed into or out from a subroutine
  • The parameters used in a procedure call are ACTUAL parameters
  • The parameters used in a procedure definition are called FORMAL parameters
  • A parameter is passed BY REFERENCE if it is to by passed into and back out of a procedure
  • A parameter is passed BY VALUE if it is to by passed into but NOT back out of a procedure
  • Arrays are ALWAYS passed by reference
  • The use of parameters means that variables can be kept local to subroutines
  • This leads to programs being more reliable and robust