best practices in coding

Some basic issues in every development team
fundamental discipline issues in coding
number of years of exp. does not match delivery
by the time they actually become good coders, they are promoted to leads
70% of the whole employees, belong 0-4 years of experience

In India, senior developer means 3-5 years of exp, in USA, senior developer means 6-10 years of exp – There is a huge gap in expectation and quality

Coding is not rocket science

The rework time in coding is the actual killer
20-25% of the time is spent in reworking in software – that means, fix the mistakes done
In a mobile phone, can you insert sim card wrongly? You cannot. Because the sim card design is like that. So the highest level maturity is not to give an opportunity to make mistakes

As a kid, you were asked and helped to brush the teeth. It was tough to brush teeth.
One fine morning, you start brushing teeth by yourselves.
Then it has become a habit. You need not be told to do brushing by anyone.
Commenting is necessary for maintaining any program
Without commenting, the program is not complete
Do not assume that the other person who reads this program will understand it clearly
If commenting is not done at the beginning, it is forgotten.

Program - a physical file – you need to comment the following at the top.
at the top of the program - header comment
what the program achieves
who coded on what day

Classes
Comment at the beginning of the class about what the class does
class Employee
// this class is used to manage all information
// about employees and retrieve specific data

Methods within classes
what this method/function/procedure does
what are the parameters and their purpose
what are the return values

Comment before every loop.

Comment before every file or database operation

Comment before every if condition
If you are team leader, if your team member comes with a code, that does not have these comments – what will you do?
You take over a program for maintenance from another person, and that program has no comments – what will you do?
Your company hands over a project to client. Programs do not have comments. What the client will say?
Readability improves understanding; that further improves maintainability
If programs are not consistent, maintenance is tough
If 20 developers work in a project and each one names functions in the way he/she wants, will the client approve the same?
We must have a document on naming conventions
Every document must be named properly and it must be stored in a proper folder.
You need to have a convention for naming
Programs
Classes
Methods
Variables
Labels in programs
Reusable library functions
There are established methods like Pascal casing, camel casing etc.
Usually you will tend to use a mixture of uppercase, lowercase letters, underscore etc
The ultimate aim is to achieve consistency across programs
Placing a number or quoted text inside active code is hard coding
This is deadly as the program restricts itself to this hard coded value
To make a change, you need to change code, recompile and redeploy
Usual way to avoid hard coding is to use constants at the top of a program; here also, you need to edit the program, but the change is in one place
Other way is to put all configurable values in a csv or ini or dat file. Every program must read the name value pair from the file and later use them in the code
Eg. MAX_LENGTH 150, PORT 8097

Modularity is important for easy maintenance
Do not write lengthy methods or procedures
We can split the modules based on
A functional operation as per requirements
A piece of code is used in more than one place
Logical breakdown of events in the functionality
Modularity must be decided right at the design level itself
Modular programs are easy to debug
Fixes done on modular programs are easy to isolate from other regression effects
A loop is - repeat some logic for specific number of times or as long as a condition is true/false
If this is not checked, it can run forever, infinitely and can bring down the server
Loop Sample
gateway 1 // variables, flags
xyz = 10
loop starts here
...gateway 2 // variables, flags, counters
..
logic
... gateway 3
loop ends here
gateway 4
Gateways are the check posts where we must watch the value of the variables, loop counters and loop flags
Ensure proper resetting of flags and counters and check their values and gateways of the loops
Never allocate memory inside a loop
Never instantiate a class inside a loop; if needed, close it within the loop
Usually companies do not suggest more than 3 levels in the loops

Issues may be caused by programmer
Issues may be caused by system
Most of the languages allow try-catch or on-error-goto exceptions

Exception is also an error condition
we do not know when it will happen

1. Any file operations – handle exceptions, because
file may not exist
file is already opened by someone
file does not have privilege
file is already full

2. Any database operation – handle exceptions, because
database you may not have rights
database is down
connections exhausted

3. Memory
low memory exception
pointers - writing in privileged memory
array boundary breach

4. Any external evices
your program accesses webcam or printer
We need to monitor cpu, memory, network

Memory is directly related to variables and object – do not declare huge arrays or objects

Cpu is consumed more when you deal with db or files or devices

Any database operations, open late and close the connection early.

Usage of indexes in queries must be examined

Any column used in where condition of db query must have index on it

Any memory allocated must be freed – else the program will shut down after some time

Any object instantiated must be released – else system will be depleted of memory and hence performance will come down
Usually the logic design will be provided to the developer
If it is not provided, take 30 minutes and write the logic of the program in English first
Do not start coding right away. You will make so many assumptions and it will spoil the show
Get the logic approved by the team lead and then start coding
Developers usually feel that this takes time; but it reduces the time effectively while coding and reworking
Since developers are not used to documenting, they feel it is not their job. Hence they miss a lot of finer points
If you write the logic first, you will get a lot of clarifications at that time itself and hence the code will come out clean