1 Pseudocode For Program Design

22 Rules for Pseudocode Write only one statement per line Capitalise initial keyword Indent to show hierarchy and structures End multiline structures Keep statements language independent Remember you are describing a logic plan to develop a program, you are not programming!

33 One Statement Per Line Each statement in pseudocode should express just one action for the computer. Note capitals for the initial keywords These are just a few of the keywords to use, others include READ, WRITE, IF, ELSE, ENDIF, WHILE, ENDWHILE Pseudocode READ name, hoursWorked, payRate gross = hoursWorked * payRate WRITE name, hoursWorked, gross Pseudocode READ name, hoursWorked, payRate gross = hoursWorked * payRate WRITE name, hoursWorked, gross

44 Indent to Show Hierarchy Sequence: Keep statements in sequence all starting in the same column Selection: IF, ELSE (or ELSEIF), ENDIF must be in line Indent all statements that depend on a condition Loop: WHILE, ENDWHILE Indent statements that fall inside the loop but not keywords that form the loop Also REPEAT, UNTIL READ name, grossPay, taxes IF taxes > 0 net = grossPay – taxes ELSE net = grossPay ENDIF WRITE name, net READ name, grossPay, taxes IF taxes > 0 net = grossPay – taxes ELSE net = grossPay ENDIF WRITE name, net count = 0 WHILE count < 10 ADD 1 to count WRITE count ENDWHILE WRITE “The End” count = 0 WHILE count < 10 ADD 1 to count WRITE count ENDWHILE WRITE “The End”

55 The Looping Structure Pseudocode uses specific keywords to designate looping WHILE / ENDWHILE: condition checked before loop REPEAT / UNTIL: condition checked after loop

66 WHILE / ENDWHILE count = 0 WHILE count < 10 ADD 1 to count WRITE count ENDWHILE WRITE “The End” REPEAT / UNTIL count = 0 REPEAT ADD 1 to count WRITE count UNTIL count >= 10 WRITE “The End”

77 Multiple Decisions Example: the postage charged by Nation Couriers is Calculated on the weight of the parcel. < 2 kg$ – 5 kg$ $1 per kg over 2 kg > 5 kg$8 + $1 per kg over 5 kg READ weight CASE weight OF less than 2 : cost = $4.50 between 2 and 5 : cost = $ (weight – 2) greater than 5 : cost = $8 + (weight -5) END CASE PRINT cost