Learning to write clean code is hard work. We need to practice it heavily to achieve that skill.
1. Clean Code
We spend most of the time reading code before writing it. So, it is important to write clean code.
2. Meaningful Names
Take time to name variables and functions. If we find a better name at later point of time, make the code better by replacing it.
The variable name should reveal the intent. Eg: elapsedTimeInDays.
Avoid chances of disinformation while naming. A variable with name accountList gives a perception to developer that it might be a list. If its not, do not provide that name. Simply put accounts or accountGroup.
Every now and then we use the search in files option in our IDE. So having search friendly approach in using variable names and constants will be great. Rather than using 12 as rate of interest, use a constant RATE_OF_INTEREST with value 12. Searching for RATE_OF_INTEREST gives the intended result faster than searching for 12.
Classes and objects should take the name of a noun. Eg: user, account
Method names should take the name of a verb. Eg: save, calculateInterest
3. Functions
Functions should be small. Try to keep it below 20 lines.
When writing if-else block or while loop, try to keep each block to one line. That one line can be a function call. The called function's descriptive name improves readability.
Functions should do only one thing and they should do it well.
When reading through a function, it should have a top-down narrative. When details are mixed with essential concepts, it is difficult to read.
If a function contains switch statment, there is a high chance that the function will be big. Also, the switch statment cases might need to be added or removed in the long run. Also, other related functions might also use the same switch statement. In this case, we need to try to abstract the switch statement itself in an Abstract Factory. Then make use of the interface in other functions.
Use descriptive names for functions. If a function performs what you expected from the name, it is clean code. A long descriptive name is better than a long descriptive comment.
Joby Joseph