Coding - Book and Reading

Structured ProgrammingThe core of structured programming is the simple idea that a program should use only one-in, one-out control constructs.. Coding time use of magic numbers 2.. Load

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Books And Reading

There is no course textbook Here are some useful books:

• Code Complete, Second Edition by Steve McConnell, 2004

Structured Programming

The core of structured programming is the simple idea that a program should use only one-in, one-out control constructs

Selection

Iteration Sequence

temp = Sqrt( b*b - 4*a*c );

root[0] = ( -b + temp ) / ( 2 * a );

root[1] = ( -b - temp ) / ( 2 * a );

// swap the roots

temp = root[0];

root[0] = root[1];

root[1] = temp;

Binding Time

1 Coding time (use of magic numbers)

2 Compile time (use of a named constant)

3 Load time (reading a value from an external source such as the Windows registry file or a Java properties file at program load time)

4 Object instantiation time (such as reading the value each time a window is created)

5 Just in time (such as reading the value each time the window is drawn)

Using Each Variable for Exactly One

Purpose

The earlier the binding time, the lower the flexibility and the lower the complexity

Live Time

Keep Variables "Live" for as Short a Time as Possible

1 // initialize all variables

2 recordIndex = 0;

3 total = 0;

4 done = false;

26 while ( recordIndex < recordCount ) {

27

28 recordIndex = recordIndex + 1; < 1

64 while ( !done ) {

69 if ( total > projectedTotal ) { < 2

70 done = true; < 3

recordIndex

( line 28 - line 2 + 1 ) = 27

total

( line 69 - line 3 + 1 ) = 67

done

( line 70 - line 4 + 1 ) = 67 Average Live Time

( 27 + 67 + 67 ) / 3 = 54

Deep Nesting

Avoiding nesting to more than three or four levels

if ( inputStatus == InputStatus_Success ) {

// lots of code

if ( printerRoutine != NULL ) {

// lots of code

if ( SetupPage() ) {

// lots of code

if ( AllocMem( &printData ) ) {

// lots of code

}

}

}

}

Retesting

Return

if-then-elses

case

GoTo

Routines

Polymorphism

Exceptions

Redesign

Make things as simple as possible but no simpler

Albert Einstein

if ( ( (status = Success) and done ) or

( not done and ( numLines >= maxLines

) ) ) then

1 Start with 1 for the straight path through the routine

2 Add 1 for each of the following

keywords, or their equivalents: if

while repeat for and or

3 Add 1 for each case in a case

statement

0 5

The routine is probably fine

6 10

Start to think about ways to simplify the

routine

10+

Break part of the routine into a second

routine and call it from the first routine

Boolean Expressions

if (!statusOK) {

// do something

}

else {

// do something else

}

if ( !displayOK || !printerOK )

while ( i < MAX_ELEMENTS and item[ i ] <> 0 )

if ( ( ( item / denominator ) > MIN_VALUE ) && ( denominator != 0 ) )

if ( i > MIN_ELEMENTS ) and ( i < MAX_ELEMENTS )

if (i < MIN_ELEMENTS or i > MAX_ELEMENTS)

How Long Can a Routine Be?

200

How to Use Routine Parameters? input-modify-output

Pseudocode Programming Process

- PPP

Test-Driven Development TDD

Direct Access Tables

Insurance Rates (Gender, Marital Status,

Smoking Status, Age)

if ( gender == Gender.Female ) {

if ( maritalStatus == MaritalStatus.Single ) {

if ( smokingStatus ==

SmokingStatus.NonSmoking ) {

if ( age < 18 ) { rate = 200.00;}

else if ( age == 18 ) {rate = 250.00;}

else if ( age == 19 ) {rate = 300.00;}

A table-driven method is a scheme that allows

you to look up information in a table rather

than using logic statements (if and case) to

figure it out

Day-In-Month

If ( month = 1 ) Then days = 31

ElseIf ( month = 2 ) Then days = 28

ElseIf ( month = 3 ) Then days = 31

Indexed Access Tables

Rather than being accessed directly, an indexed access table is accessed via an intermediate index

9999

0000

When you use indexes, you use the primary data to look up a key in an index table and then you use the value from the index table to look up the main data you're interested in

1

100

Stair-Step Access Tables

The stair-step approach categorizes each entry by determining the level at which

it hits a "staircase." The "step" it hits determines its category

< 8.5 C

< 7.5 E

To use the stair-step method, you put the upper end of each range into a table and then write a loop to check a score against the upper end of each range When you find the point at which the score first exceeds the top of a range, you know what the grade is

Thank you for your time