Algorithm specification test questions

What is the purpose of an input validation algorithm?

To make sure that all variables are correctly initialised by the programmer

To make sure that data received from the user is valid for the task at hand

To make sure that all output is validated before it is sent from the program

Which of the following is an example of a pre-test conditional loop often used as part of input validation algorithms?

IF…THEN…ELSE…END IF

WHILE…END WHILE

FOR EACH...FROM...DO...END FOR EACH

Which of the following is an example of a post-test conditional loop, sometimes used as part of input validation algorithms?

REPEAT…UNTIL

FOR…FROM…TO…DO…END FOR

SET…TO…

The algorithm shown below will keep a running total. Which line shows the start of a fixed loop?

Line 1 DECLARE total INITIALLY 0

Line 2 DECLARE numberlist INITIALLY [3, 45, 17, 21, 26]

Line 3 FOR EACH number FROM numberlist DO

Line 4 SET total TO total + number

Line 5 END FOR EACH

Line 2

Line 3

Line 5

The algorithm shown below is an example of which of the three algorithms that must be understood at this level?

Line 1 DECLARE total INITIALLY 0

Line 2 FOR loop FROM 0 TO 4 DO

Line 3 RECEIVE number FROM (INTEGER) KEYBOARD

Line 4 SET total TO total + number

Line 5 END FOR

Input validation

Traversing a 1D array

Running total within loop

Which of the following describes ‘traversing an array’

Access each element in an array so that data can be checked, altered or used

Check that data entered is valid

Keep a running total of values held in separate variables that do not make use of an array structure