Programming

Question 1

Algorithm

Answer 1

A series of instructions / sequence of steps designed to perform a particular task or solve a problem

Question 2

Types of conditional statement

Answer 2

1. IF… THEN… ELSE… ENDIF

2. CASE… OF… OTHERWISE… ENDCASE

Question 3

Types of loop structure & their description

Answer 3

1. FOR… TO… NEXT
   - a set number of iterations
2. WHILE… DO… ENDWHILE
   - used where the loop may never be executed
   - whilst a specific condition exists
3. REPEAT… UNTIL
   - always executed
   - condition tested at end

Question 4

Types of test data & reason for use

Answer 4

1. Normal data
   - Acceptable data to test that the results are as expected
2. Abnormal data
   - Data that should be rejected and produce an error message
3. Extreme data / Boundary data
   - Data to test the validation that is just within the limits of acceptability

Question 5

Difference between a variable and a constant in a program

Answer 5

A variable is used to store data that can change during the running of a program.
A constant is used to store data that will not be changed during the running of a program.

Question 6

7 types of validation checks

Answer 6

1. Range check
2. Length check
3. Type check
4. Character check
5. Format check
6. Presence check
7. Check digit

Question 7

4 types of verification checks

Answer 7

1. Double entry
2. Screen/visual check
3. Parity check
4. Checksum

Question 8

Use of variable ‘Counter’

Answer 8

To use as a loop counter when entering … (eg. the temperatures)

Question 9

Comment on the efficiency of your design for Task 3.

Answer 9

1. Only checks necessary conditions

2. Uses results from Task 2

Question 10

Reason for use of data structure ‘Array’

Answer 10

1. To simplify programming
2. To make programs shorter
   * If using ‘several arrays’, index can be used to identify the same __ (eg. member) across the arrays

Question 11

Describe the data type Char.

Answer 11

A single character (from the keyboard)

Question 12

Describe the data type String.

Answer 12

An (ordered) sequence of characters

Question 13

Describe the data type Boolean.

Answer 13

A data type with two possible values

Question 14

Describe the purpose of a conditional statement.

Answer 14

• to allow different routes through a program

- dependent on meeting certain criteria

Question 15

Validation

Answer 15

• automated checking
• checking that data is reasonable
• checking that data meets certain criteria

Question 16

Verification

Answer 16

• checking that data has not changed…
• … during input to a computer
• … during transfer between computer/devices
• check that data input is the same as the data that was intended to be input

Question 17

Explain what is meant by the term library routine.

Answer 17

• Library routine is a set of instructions
• …that is used often…
• …which is given a name
• …and which can be called from other programs
• Library routines make writing programs easier and faster as the code is already written
• Library routines make program testing easier as the code has already been tested and debugged