Writing Quality Code
Hitesh A. Bosamiya
Technical Architect – Software Expert
HP Software - Big Data, India
April 23, 2015
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Who is the Bravest?
Client
Test
Team
Q.A. Manager
Team Lead /
Scrum Master
P.M.
Developer
BUG!!!
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Source: Solid Private and Commercial Security Services
Confident
3
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Introspective
4
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Take Away
Writing Quality Code
5
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About Me
6
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Dictionary Definitions
Quality
• the character in a logical proposition of being affirmative or
negative
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Dictionary Definitions
Quality
• the character in a logical proposition of being affirmative or
negative
Code
• a set of instructions for a computer
8
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Dictionary Definitions
Quality
• the character in a logical proposition of being affirmative or
negative
Code
• a set of instructions for a computer
Program
• a plan or system under which action may be taken toward a goal
9
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Dictionary Definitions
Quality
• the character in a logical proposition of being affirmative or
negative
Code
• a set of instructions for a computer
Program
• a plan or system under which action may be taken toward a goal
Programming
• to work out a sequence of operations to be performed by (a
mechanism)
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A Quick Glance at Quality Process
Code Review Process & It’s Effectiveness
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Developer
Reviewer
Quality
0
0
Suffers
0
1
May Suffer
1
0
May Suffer
1
1
Good
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A Quick Glance at Quality Metrics
Defect Density
Artifact
Original Code
Modified Code
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KLO
Defect Density
Defects
C
(Defects/KLOC)
16.5
2.0
33
9.3
3.5
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Myth vs. Reality
Myth
The code is not seen by the customer
Reality
The product is seen by the customer
• Which in-turn made out of code, not of the design document!!!
• Does this mean that the design is not important?
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“Know one level below”
i.e.
“Know what is under the hood”
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Why One Level Below?
Experience 1 – Self Modifying Code
CMP AX, 0001H
JNE instr_to_change
MOV WORD PTR [instr_to_change + 1], 0B0CH
instr_to_change:
MOV CX, 0000H ; or MOV CX, 0B0CH
NOP
NOP
NOP
NOP
NOP
NOP
Experience 2 – C Compiler Release Mode Optimization
Assembly
Language
Microprocessor
Architecture
C/C++
Assembly
Language
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Applicability
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Assembly
Language
C/C++
Java
NodeJS
Microprocessor
Architecture
Assembly
Language
JVM
Event Loop
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“Let the dirty work be done by the
computer” - Unknown
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A Simple Example
Date selector in dynamically generated HTML page
// repetition of code
print("<OPTION>1</OPTION>");
print("<OPTION>2</OPTION>");
print("<OPTION>3</OPTION>");
...
...
...
print("<OPTION>31</OPTION>");
// Using logic
final int MAX_DAYS_IN_MONTH = 31;
for (int i = 1;
i <= MAX_DAYS_IN_MONTH;
i++) {
print("<OPTION>" +
i +
"</OPTION>");
}
Advantages
Programming Pride, Extensibility, Maintainability
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Limit function/method size
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An Example
Original Code
20
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An Example
Modified Code – One Screen Full!
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“Any fool can write code that a
computer can understand.
Good programmers write code that
humans can understand.”
Martin Fowler
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Don’t State the Obvious
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No “Divide by 2” Comments
public void myMethod(int foo) {
...
if (foo == 2) {
for (int i = 0; i < myMax; i++) {
while (true) {
...
} // end while
} // end for
} // end if
} // end myMethod(int)
// TODO: Add
// Following
// commented
/*
...
...
String s =
*/
Comment Here
code has been
out
“Hello World!”;
DIV AX, 2 ; Divide by 2
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Readable Code
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Less Comments in the Readable Code
•
•
•
•
•
•
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Know the problem domain
Normal conditions should follow error conditions
Refactor
Remove unused code
Learn multiple languages
Comments only for complex logic and generating the document
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An Example
Original Code
27
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An Example
Original Code
28
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An Example
Original Code – With Comments
29
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An Example
Original Code – With Comments
30
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An Example
Modified Code
31
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An Example
Modified Code
32
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Connecting the Dots
Writing Quality Code
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Q&A
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Thank you
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