W3 - LOGIC

Question 1

W3-1 What is STRUCTURED PROGRAMMING? (SP)

Answer 1

_ is a programming PARADIGM aimed at improving the clarity, quality, and development time of a computer programming

_ SP consists of sets of simple CONSTRUCTS, each of which has 1 ENTRY point and 1 EXIT point.

Question 2

W3-2 SEQUENTIAL CONSTRUCTS represent?

Answer 2

one statement follows another and the statements are executed in order

• SELECTION constructs and ITERATION constructs represent MODIFICATIONS of sequential constructs.

Question 3

W3-2 SELECTION CONSTRUCTS represent?

Answer 3

different paths through the sets of instructions

Question 4

W3-3 ITERATION CONSTRUCTS represent?

Answer 4

REPETITION of the SAME set of instructions until a specified condition has been met.

Question 5

W3-4 To complete a programming language, how many classes of constructs are required?

Answer 5

3 classes of constructs:
1/ SEQUENTIAL CONSTRUCTS
2/ SELECTION CONSTRUCTS
3/ ITERATION CONSTUCTS

Question 6

W3-5 What is the SIMPLEST example of a STRUCTURED construct?

Answer 6

_ a sequence

_ A sequence is either a SIMPLE STATEMENT or a CODE BLOCK

Question 7

W3-6 What is a CODE BLOCK?

Answer 7

_ is a set of STATEMENTS enclosed in a pair of curly braces to be executed sequentially.

_ Unlike a SINGLE STMT, a C CODE BLOCK does not require a TERMINATING semi-colon of its own (after the closing brace)

Question 8

W3-7 Well-established techniques include?

Answer 8

_ pseudo-coding
_ flow-charting
=> improve chances are that our coding will be clear and concise

Question 9

W3-8 What is a PSEUDO-CODE?

Answer 9

is a set of shorthand NOTES in a human (non-programming) language that itemizes the KEY steps in the sequence of instructions that produce a programming solution.

Question 10

W3-9 What is a FLOW CHART?

Answer 10

is a set of conventional SYMBOLS connected by arrows that illustrate the FLOW of control through a programming solution.

Question 11

W3-10 The C language supports 3 SELECTION CONSTRUCTS?

Answer 11

_ OPTIONAL path (OP)
_ ALTERNATIVE paths (AP)
_ CONDITIONAL expression (CE)

Question 12

W3-11 OPTIONAL PATH executes?

Answer 12

_ a SEQUENCE only if a certain condition is satisfied; that is, if the condition is TRUE.

_ OPTIONAL selection takes the form
if (condition)
sequence

• Parentheses enclose the condition, which may be a RELATIONAL expression or a LOGICAL expression
• The sequence may be a SINGLE STMT or a CODE BLOCK

Question 13

W3-12 C language supports 2 ways of describing ALTERNATIVE PATHS?

Answer 13

_ an binary select construct

_ a multiple selection construct

Question 14

W3-13 BINARY SELECTION CONSTRUCT executes?

Answer 14

_ one of a set of ALTERNATIVE SEQUENCES

_ Construct takes the form
if (condition)
            sequence
else
            sequence

• Parentheses enclose the condition, which may be a RELATIONAL expression or a LOGICAL expression
• The sequences may be SINGLE STMTs or CODE BLOCKS
• (P) executes the sequence following the IF only if the condition is TRUE
• (P) executes the sequence following the ELSE only if the condition is FALSE

Question 15

W3-14 MULTIPLE SELECTION

Answer 15

For 3 alternative paths

=> append an IF ELSE construct to the ELSE keyword

Question 16

W3-15 COMPOUND CONDITION

Answer 16

_ The CONDITION in a selection construct may be a COMPOUND CONDITION

_ A COMPOUND CONDITION takes the form of a LOGICAL EXPRESSION

Question 17

W3-16 CASE-BY-CASE selection construct

Answer 17

compares a CONDITION - simple or compound - against a set of CONSTANT values or constant expressions.

_ This construct takes the form:
switch (condition) {
case constant:
              sequence
              break;
case constant:
              sequence
              break;
default:
              sequence
}

Question 18

W3-17 What is CONDITIONAL SELECTION CONSTRUCT?

Answer 18

is shorthand for the ALTERNATIVE path constuct

_ This TERNARY expression combines a condition and 2 sub-expressions using the ? : operator
condition ? operand : operand

Question 19

W3-18 C language supports 3 ITERATION CONSTRUCTS?

Answer 19

_ while
_ do while
_ for

Question 20

W3-19 What is an INFINITE LOOP?

Answer 20

If the CHANGE STMT is MISSING or if the TEST condition is always SATISFIED, the iteration continues without terminating and the program can NEVER terminate.
=> such an iteration is an INFINITE LOOP

Question 21

W3-20 The WHILE construct

Answer 21

executes its sequence as long as the test condition is TRUE.

_ This construct takes the form:
while (condition)
sequence

Question 22

W3-21 The DO WHILE construct

Answer 22

executes its sequence at least ONCE and continues executing it as long as the test condition is TRUE.

_ This construct takes the form:
do
sequence
while (condition);

Question 23

W3-22 The FOR construct

Answer 23

groups the initialization, test condition and change together, seperating them with semi-colons.

_ This construct takes the form:
for (initialization; condition; change)
sequence

Question 24

W3-23 What is FLAGGING?

Answer 24

is a METHOD of coding iteration constructs within the SINGLE-ENTRY SINGLE-EXIT rule of structured programming.

Question 25

W3-24 What are FLAGS?

Answer 25

_ are VARIABLES that determine whether an iteration continues or stops

_ A flag is either TRUE or FALSE

_ Flags help ensure that NO paths cross one another.

Question 26

W3-25 What is NESTING?

Answer 26

enclosing one LOGIC construct within another

Question 27

W3-26 What is a NESTED SELECTION?

Answer 27

a selection within another selection

Question 28

W3-27 What is DANGLING ELSE?

Answer 28

_ An ambiguity arises in a nested IF ELSE construct that contains an optional sequence (if)

_ (C) always attaches the dangling ELSE to the innermost IF.

Question 29

W3-28 What is a NESTED ITERATION?

Answer 29

an iteration within another iteration