Code Complete ---- (Note 5 Statements)

Code Complete ---- (Part 5 Statements)

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1. Organizing Straight-Line Code

Statements that must be in a speicific order
---- Organize code so that dependencies are obvious.


Statements whose order doesn't matter
---- Grouping related statements

DataA                  
OperateDataA;  
.....                        
 
DataB                 
OperateDataB; 
.....                       

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2. Using Conditions

IF-ELSE ...
--- Put the normal case after the 'if' rather than after the 'else'.
--- Consider teh else clause
    ---- Code the else clause or with a null statement with some comments
---- Simplify complicated tests with boolean function calls
---- Put the most common cases first
---- Make sure that all cases are covered
     Code a final else clause with an error message or assertion to catch cases you didn't plan for.

Case
---- Choosing the most effective ordering of cases
     --- order cases alphabetically or numerically
     --- put the normal case first
     --- Order cases by frequency
---- Use the default clause only to detect legitimate defaults, and to detect errors

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3. Controlling Loops

****When to Use Loop-With-Exit Loop****

score = 0;
GetNextRating(&ratingIncrement);
rating += ratingIncrement;
while(condition....)...{
    GetNextScore(&scoreIncrement);
    score += scoreIncrement;
    GetNextRating(&ratingIncrement);
    rating += ratingIncrement;
}

// Code Repeated and that isn't easy to maitain

score = 0;
while(true)...{
    GetNextRating(&ratingIncrement);
    rating += ratingIncrement;

    if (!condition...)
        break;

    GetNextScore(&scoreIncrement);
    score += scoreIncrement;
}

//Notice: Put all the exit conditions in one place

Don't monkey with the loop index of a for loop to make the loop terminate
---- when u set up a for loop, the loop counter is off limits, use a while loop to provide more control over the loop's exit conditions.

Avoid code that depends on the loop index's final value

int recordCount = 0;
for (; recordCount < MAX_RECORD; ++recordCount)...{
    if (Entry[recordCount] == testValue)
        break
          //......

    if (recordCount < MaxRECORD)
        return true;
    else
        return false;
}

// It's easy to make an off-by-one error

...{
    bool found = false;
    for (; recordCount < MAX_RECORD; ++recordCount)...{
        if (Entry[recordCount] == testValue)...{
            found = true;
            break;
        } //end if
    } //end for

    ......

    return false;
}

Consider using safety counters

safetyCounter = 0;

do ...{

   node = node->Next;

   ...

   safetyCounter++;      

   if ( safetyCounter >= SAFETY_LIMIT ) ...{

      Assert( false, "Internal Error: Safety-Counter Violation." );      

   }

   ...

} while ( node->Next != NULL );
// for critical loops

Use 'continue' for tests at the top of a loop

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4. Unusual Control Structures

Mutilple Returns from a routine

Recursion
---- Make sure the recursion stops
---- Use safety counters to prevent infinite recursion

**--** Don't use recursion for factorials or Fibonacci numbers

int Factorial( int number ) ...{
   if ( number == 1 ) ...{
      return 1;
   }
   else ...{
      return number * Factorial( number - 1 );
   }
}

//

int Factorial( int number ) ...{
   int intermediateResult = 1;
   for ( int factor = 2; factor <= number; factor++ ) ...{
      intermediateResult = intermediateResult * factor;
   }
   return intermediateResult;
}

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5. Table-Driven Methods

----- Direct Access Table

If ( month = 1 ) Then
   days = 31
ElseIf ( month = 2 ) Then
   days = 28
ElseIf ( month = 3 ) Then
   days = 31
......

Dim daysPerMonth() As Integer = ...{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
days = daysPerMonth( month-1 )


enum FieldType ...{
   FieldType_FloatingPoint,
   FieldType_Integer,
   FieldType_String,
   FieldType_TimeOfDay,
   FieldType_Boolean,
   FieldType_BitField,
   FieldType_Last = FieldType_BitField
};

......

class AbstractField ...{
   public:
   virtual void ReadAndPrint( string, FileStatus & ) = 0;
}

class FloatingPointField : public AbstractField ...{
   public:
   virtual void ReadAndPrint( string, FileStatus & ) ...{
   ...
   }
 }
.....

AbstractField* field[ Field_Last ];

field[ Field_FloatingPoint ] = new FloatingPointField();
field[ Field_Integer ] = new IntegerField();
field[ Field_String ] = new StringField();
field[ Field_TimeOfDay ] = new TimeOfDayField();
field[ Field_Boolean ] = new BooleanField();
field[ Field_BitField ] = new BitFieldField();
.....

fieldIdx = 1;     
while ( ( fieldIdx <= numFieldsInMessage ) and ( fileStatus == OK ) ) ...{
   fieldType = fieldDescription[ fieldIdx ].FieldType;
   fieldName = fieldDescription[ fieldIdx ].FieldName;
   field[ fieldType ].ReadAndPrint( fieldName, fileStatus );    
}

**** Fudging lookup keys  ******
     --- Transform the key to make it work directly
         int KeyFromAge()...{
            return max( min( 66, age), 17 );
        }

----- Indexed Access

Color Index

----- Stair-step access

Dim rangeLimit() As Double = ...{ 50.0, 65.0, 75.0, 90.0, 100.0 }
Dim grade() As String = ...{ "F", "D", "C", "B", "A" }
maxGradeLevel = grade.Length - 1
...

' assign a grade to a student based on the student's score
gradeLevel = 0
studentGrade = "A"

While ( ( studentGrade = "A" ) and ( gradeLevel < maxGradeLevel ) )
   If ( studentScore < rangeLimit( gradeLevel ) ) Then
      studentGrade = grade( gradeLevel )
   End If
   gradeLevel = gradeLevel + 1
Wend

Consider using a binary search rather than a sequential search

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6. General Control Issues

if (!statusOK) ---> if (errorDetected)

writing numeric expressions in number-line order
---- if ( MIN < i ) && ( i < MAX)

NULL Statements
--- Using DoNothing() to replace ';'.  <#define or inline>

Taming dangerously deep nesting