Algorithms Sheet 2 Identifying Control Structures

1. Match the terms sequence , binary selection , multiway selection and iteration to the descriptions that follow: a decision taken in an algorithm which can go either of two ways binary selection (b) decision taken in an algorithm which allows more than two choices multiway selection decision two decision more than two

a decision taken in an algorithm which can go either of two ways

binary selection

(b) decision taken in an algorithm which allows more than two choices

multiway selection

1. Match the terms sequence , binary selection , multiway selection and iteration to the descriptions that follow: a decision taken in the processing done by an ATM to either withdraw, deposit or check account balance, depending on the key pressed multiway selection (d) a loop in a process which repeats the same instructions a number of times iteration decision more than two repeats

a decision taken in the processing done by an ATM to either withdraw, deposit or check account balance, depending on the key pressed

multiway selection

(d) a loop in a process which repeats the same instructions a number of times

iteration

1. Match the terms sequence , binary selection , multiway selection and iteration to the descriptions that follow: (e) a part of a program where we always add 1 to a counter and then print sequence (f) a portion of a program that is done over and over again, and only stops when the count reaches zero iteration always over and over again

(e) a part of a program where we always add 1 to a counter and then print

sequence

(f) a portion of a program that is done over and over again, and only stops when the count reaches zero

iteration

2. Identify two of the control structures used in each of the following algorithms (a) Count = 0 REPEAT DoTheLoop Add 1 to Count UNTIL Count = 5 sequence iteration/repetition sequence

(a)

Count = 0

REPEAT

DoTheLoop

Add 1 to Count

UNTIL Count = 5

sequence

iteration/repetition

sequence

2. Identify two of the control structures used in each of the following algorithms (b) WHILE Count <= 5 Add 1 to Count DoTheLoop END WHILE iteration/repetition sequence

(b)

WHILE Count <= 5

Add 1 to Count

DoTheLoop

END WHILE

iteration/repetition

sequence

2. Identify two of the control structures used in each of the following algorithms (c) Get NextVideo IF category = ‘X’ THEN print ‘You cannot watch this!’ ELSE DoBorrowProcess Print details END IF sequence selection (binary)

(c)

Get NextVideo

IF category = ‘X’

THEN print ‘You cannot watch this!’

ELSE DoBorrowProcess

Print details

END IF

sequence

selection (binary)

2. Identify two of the control structures used in each of the following algorithms (d) REPEAT Enter Number IF Number > highest THEN set highest to Number END IF UNTIL no more Numbers iteration/repetition sequence selection

(d)

REPEAT

Enter Number

IF Number > highest

THEN set highest to Number

END IF

UNTIL no more Numbers

iteration/repetition

sequence

selection

2. Identify two of the control structures used in each of the following algorithms (e) WHILE more input Select input CASE 1 DoWithdrawals CASE 2 DoDeposits CASE 3 DoAccountBalance CASE other DoErrorProcess END select Get input END WHILE iteration/repetition selection (multiway) sequence

(e)

WHILE more input

Select input

CASE 1

DoWithdrawals

CASE 2

DoDeposits

CASE 3

DoAccountBalance

CASE other

DoErrorProcess

END select

Get input

END WHILE

iteration/repetition

selection (multiway)

sequence

3. Identify the control structure other than sequence used in the following algorithms:

3. Identify the control structure other than sequence used in the following algorithms:

3. Identify the control structure other than sequence used in the following algorithms:

3. Identify the control structure other than sequence used in the following algorithms:

Remember You need to know how to apply this information, so see me for further help if you think it is necessary for you.

You need to know how to apply this information, so see me for further help if you think it is necessary for you.