A control program is being developed for a robot floor vacuum cleaner. The settings for the robot can be changed and include the strength of the suction (numerical values: 0, 1, 2, 3, 4 or 5) and the total vacuum cleaning time (a whole number of minutes).

The robot has a number of sensors. The control program includes the variables:

Variable	Description
MainsOn	TRUE when the mains power is on
DisplayOn	TRUE when the user display is shown
Suction	TRUE when the program detects that the user has selected a non-zero value for the strength of the suction

Identify the data type used for the three variables.

2(b)Operators Expressions SelectionEasy1 mark

Write a pseudocode statement to set the DisplayOn variable to TRUE when the mains power is on.

Answer

0 words

2(c)Operators Expressions SelectionMedium2 marks

When the robot is ready to move, the program assigns the value TRUE to a variable, Move. The control program contains the pseudocode logic expression:

pseudocode

01Move ← MainsOn AND Suction

Explain the pseudocode statement.

Answer

0 words

2(d)(i)Testing DebuggingEasy1 mark

The pseudocode for the control program contains the procedure CleanProgram()

pseudocode

01PROCEDURE CleanProgram()02// declaration of variables has been omitted0304Finished ← FALSE05OUTPUT "Total clean time (minutes)"06INPUT  TotalCleanTime07OUTPUT "Suction strength (0,1,2,3,4,5)"08INPUT  SuctionStrength0910WHILE Finished = FALSE11   // TimeSoFar is a global variable which changes12   // as the procedure is executed13   // TimeSoFar is the time the robot has been cleaning (in seconds)1415   TimeRemaining ← TotalCleanTime - INT(TimeSoFar/60)1617ENDWHILE1819ENDPROCEDURE

When the program is under development and running, the programmer can temporarily stop the execution at a set point in the program. Identify this feature of the Integrated Development Environment (IDE).

2(d)(ii)Data Types Variables Input OutputEasy1 mark

The programmer runs the program. The user is prompted and inputs the value 40 (total clean time in minutes). The user is prompted and inputs the value 3 (for the suction strength). The programmer interrupts its execution; the TimeSoFar is shown in a report window as 125 (the cleaning time so far in seconds). State the current value of TimeRemaining

Answer