Software Development

Question 1

Coding:

Answer 1

how alphanumeric data and control characters are represented by sequences of bits

Question 2

American Standard Code for Information Interchange (ASCII)

Answer 2

• 7-bit code permitting (2)^7 = 128 different combinations

- commonly used in desktop computers

Question 3

Extended Binary Coded Decimal Interchange Code (EBCDIC)

Answer 3

• used in IBM mainframe computers

- 8-bit code permitting (2)^8 =256 different characters

Question 4

program

Answer 4

sequence of computer instructions that perform some function
- designed to implement an algorithm

Question 5

algorithm

Answer 5

procedure consisting of a finite set of well-defined steps

Question 6

source code statements:

Answer 6

• instructions like READ, GOTO, OPEN

- translated into machine-readable object code to produce executable program

Question 7

variable

Answer 7

• used by a program to store a value

- can be known or unknown

Question 8

declaration

Answer 8

• defines a variable
• specifies the type of data a variable can contain
• reserves space for the variable in the program’s memory

Question 9

assignment

Answer 9

give values to variable

Question 10

command:

Answer 10

instructs the program to take specific action

Question 11

function:

Answer 11

specific operation grouped into a unit that can be called within the program

Question 12

flowchart

Answer 12

• step by step representation of a specific procedure or algorithm
• -> terminal: begins and ends flowchart (pill shaped)
• -> input/output: defines an i/o operation (rhombus)
• -> processing: defines a calculation or data manipulation (rectangle)
• -> predefined process (subroutine): refers to a calculation or data manipulation formally defined elsewhere (square with stripes on left and right sides)
• -> decision: indicates a branch or question in the process flow (typically two options, such as yes and no) (diamond)
• -> connector: indicates flowchart continues elsewhere (circle)
• -> off-page: indicates flowchart continues on following page (looks like home base plate)
• -> annotation: indicates a comment (rectangle with dotted line)

Question 13

machine language instructions:

Answer 13

• compatible with and readily understood by the central processing unit (CPU)
• each instruction must be expressed as a series of bits (intrinsic machine code)
• may be written in octal or hexadecimal for convenience, then converted to binary
• instructions consists of op-codes and operands
• -> op code : operation to be performed
• -> operand: storage location

Question 14

assembly language

Answer 14

• next-higher -level language above machine language
• mnemonic codes specify operations
• operands referred to by variable name rather than address

Question 15

macros

Answer 15

• blocks of code repeated verbatim at multiple locations in a program
• written once and the referred to by a symbolic name

Question 16

assembler

Answer 16

• translates assembly language into machine language

Question 17

linker

Answer 17

• combines portions of other programs or function libraries after assembly

Question 18

loader

Answer 18

places the program in the computer’s memory in order to run it

Question 19

A portion of computer code contains the instructions LR, SC and JL. Most likely these are A) machine language B) assembly language C) object code D) interpreted code

Answer 19

B) assembly language
–> assembly language usually consists of short commands such as LR for loading a value into the register, SC for storing a result in location C, and JL for jumping if the result is less than a given number. Assembly language is translated into binary machine language (also known as “object code”) by an interpreter or compiler program

Question 20

relative computational speed languages

Answer 20

slower faster
<——————————————————————————————————————————————————————————–>
interpreted program pseudo-compiled compiled assembly language

Question 21

structure:

Answer 21

in a structural language, each subroutine and other procedure has one specific entry point and one specific return point.

Question 22

strong data typing

Answer 22

• different types of data are defined and cannot be interchanged
• for example, integers and real number cannot be combined in arithmetic statements

Question 23

weak data typing

Answer 23

• data of one type can be used where data of another type is expected
• for example, the number 3 can be added to the alphanumerical string “4” to get 7. (in a strongly typed language, this would probably result in an error.)

Question 24

portability

Answer 24

a portable language can be implemented on different machines

Question 25

structured programming

Answer 25

- divides a procedure or algorithm into parts: - -> subprograms - -> subroutines - -> modules - -> blocks - -> procedures

Question 26

Recursive calls

Answer 26

- permits a subprogram to call itself | - requires less code, but uses more memory

Question 27

order of operations

Answer 27

- calculations are performed in a specific order - instructions in parentheses are done first - symbols for mathematical operations + add - subtract * multiply / divide X^B may be expressed as either: X**B X^B

Question 28

Two floating point numbers, A and B are passed to recursive subroutine. If A is greater than or equal to 7, the subroutine returns the value of A. if A is greater than or equal to 7, the subroutine returns the vale of A. If A is less than the smaller of 7 and B, the subroutine divides A by 2, then passes the values of A and B to itself. Most likely what condition might this subroutine encounter? A) overflow B) miscompare) C) infinite loop D) type mismatch

Answer 28

C) infinite loop: Consider the case where A = 6 and B=9. 6 is not greater than or equal to 7, so control is note returned to the main program. 6 is less than the smaller of 7 and 9, so 6 is divided by 2, giving 3. The subroutine passes A=3 and = 9 to itself. 3 is not greater than or equal to 7, so control is not returned to the main program. 3 is less than the smaller of 7 and 9, so is 3 divided by 2, giving 1.5 The subroutine passes A=1.5 and B=9 to itself. the process repeat indefinitely because A will never be greater than 7

Question 29

IF - THEN statement

Answer 29

IF < condition > THEN < action > - fi the condition is satisfied, then the action is executed. - If the condition is not satisfied, then the action is not executed and the program moves to the next operation

Question 30

IF- THEN- ELSE statement

Answer 30

IF THEN ELSE - If the condition is satsified, then action 1 is executed - IF the condition is not satisfied, then action 2 is executed

Question 31

DO WHILE loop

Answer 31

the set of instructions after the DO WHILE instruction and before the ENDWHILE instruction is repeated as long as the condition remains true.

Question 32

DO WHILE loop

Answer 32

The set of instructions after the DO UNTIL instruction and the ENDUNTIL instruction is repeated as long as the condition remains false

Question 33

FOR loop

Answer 33

- The set of instructions after the FOR instructions and before the NEXT instruction is repeated - the counter range determines the number of loops

Question 34

GOTO

Answer 34

- moves the program to an instruction elsewhere in the program - avoided in structured programming

Question 35

A structure computer program contains the following program segment. ``` Set G= 1 and X=0 DO WHILE G ≤ 5 G = G * X + 1 X = G ENDWHILE ``` ``` What is the value of G after the segment is executed? A) 5 B) 26 C) 63 D) the loop never ends ```

Answer 35

B) 26 the first execution of the WHILE loop results in G= (1) (0) + 1 = 1 X=1 the second execution of the WHILE loop results in G= (1) (1) + 1 =2 X =2 The 3rd execution of the WHILE loop results in G= (2) (2) + 1 = 5 X = 5 The WHILE condition is still satisfied, so the instruction is executed a fourth time G= (5) (5) + 1 =26 X = 26

Question 36

modular programming

Answer 36

- builds efficient larger applications from smaller parts ( modules )

Question 37

object- oriented programming ( OOP)

Answer 37

- uses modular programming - deals with objects, which are data structures (databases) and their associated functionalities - exhibits characteristics like class, inheritance, data hiding, data abstraction, polymorphism, encapsulation, interference, and package examples: Java, C ++, Python

Question 38

Hierarchy of Operations

Answer 38

1. operations within parentheses - -> innermost pair first working outwards 2. exponentiation - -> right to left 3. multiplication and division - -> left to right 4. addition and subtraction - -> left to right

Question 39

Simulator

Answer 39

computer program that replicates a real-world system

Question 40

digital model

Answer 40

- used in simulations, incorporating variables representing physical characteristics and properties of simulated system - used to gain understanding of system's characteristics and dynamics - can be used to test multiple design scenarios

Question 41

record

Answer 41

- collection of fields | - for example, a personnel record containing the fields name, age, and address

Question 42

file

Answer 42

storage for groups of records

Question 43

sequential file structure

Answer 43

- contains consecutive records and is read starting from beginning - typical of data on magnetic tape