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A computer program is a set of instructions fed to a computer to carry out a particular task. A language used to write a computer program is called programming language. There are different styles of writing a computer program and modular programming is one such style.
What is Modular Programming?
Modular programming is the process of subdividing a computer program into separate sub-programs. These sub-programs are generally referred to as functions, modules, procedures, subroutines, etc. A module is a separate software component. It can often be used in a variety of applications and functions with other components of the system.
Each and every modular application has a version number associated with it. This provides developers flexibility in module maintenance. If any changes have to be applied to a module, only the affected subroutines have to be changed. This makes the program easier to read and understand.
Modular programming has a main module and many auxiliary modules. The main module is compiled as an executable (EXE), which calls the auxiliary module functions. Auxiliary modules exist as separate executable files, which load when the main EXE runs. Each module has a unique name assigned in the PROGRAM statement. Function names across modules should be unique for easy access if functions used by the main module must be exported.
Languages that support the module concept are IBM Assembler, COBOL, RPG, FORTRAN, Morpho, Zonnon, and Erlang, among others.
- Some programs might have thousands or millions of lines and to manage such programs it becomes quite difficult as there might be too many syntax errors or logical errors present in the program, so to manage such types of programs the concept of modular programming approached.
- Each sub-module contains something necessary to execute only one aspect of the desired functionality.
- Modular programming emphasizes breaking large programs into small problems to increase the maintainability, readability of the code and to make the program handy to make any changes in the future or to correct the errors.
Why Does Modularity Exist?
Modularity exists entirely because of the human side of development. A computer doesn’t need a broken-down and embellished version of the code to be able to run it. It’s our own cognitive limitations that force us to write code in smaller pieces.
A particular area where this becomes obvious is in dealing with temporary contexts. For example, say you’re writing to a file, but a condition arises where you need to write to another file. You need to temporarily forget about the first file and all of its related data to deal with the second one instead.
This kind of situation was confusing and overwhelming, so functions were invented. A typical way to handle this now is by making a function that writes arbitrary data to any file to isolate the temporary context inside it.
Points to Consider for Modular Program Development
Following are the points that should be kept in mind while writing a modular program:
- Limitations of each and every module should be decided.
- In which way a program is to be partitioned into different modules.
- Communication among different modules of the code for proper execution of the entire program.
Advantages of Using Modular Programming Approach
Some of the important advantages of using the modular programming approach are the following:
- Less code has to be written.
- A single procedure can be developed for reuse, eliminating the need to retype the code many times.
- Programs can be designed more easily because a small team deals with only a small part of the entire code.
- Modular programming allows many programmers to collaborate on the same application.
- The code is stored across multiple files.
- Code is short, simple and easy to understand.
- Errors can easily be identified, as they are localized to a subroutine or function.
- The same code can be used in many applications.
- The scoping of variables can easily be controlled.
Disadvantages of Using Modular Programming Approach
Although having advantages of modular programming, there are some disadvantages also such as:
- There is a need for extra time and budget for a product in modular programming.
- It is a challenging task to combine all the modules.
- Careful documentation is required so that other program modules are not affected.
- Some modules may partly repeat the task performed by other modules. Hence, Modular programs need more memory space and extra time for execution.
- Integrating various modules into a single program may not be a task because different people working on the design of different modules may not have the same style.
- It reduces the program’s efficiency because testing and debugging are time-consuming, where each function contains a thousand lines of code.
Tips to Write Modular Program
Following are the important tips that can be used to get the best of modular programming approach:
1. Isolate all logical expressions using variables
You can handle every temporary context by inserting logic in the variables. A developer should take advantage of the fact that logical expressions reduce to the Boolean value. Almost every programming language allows you to do this. Such small ideas of modularization are important since they help you understand the code has a continuous flow, like a story. It will not appear like a pattern of formulas that are not connected. For every change you make to your code, try to understand if the change helps in improving the logic. You should not make changes to code only to make it less coherent.
2. Use nested functions to summarize any code blocks
When you are writing code you might realize some repetition, and that repetition prompts you to create another independent function. Most languages allow developers to develop a new function using the same namespace, and this is where the significance of nested functions comes into play. A developer can place one function in another, so the original method can help to access the internal function. If you use IDEs with code folding, this technique becomes interesting. The IDEs allow you, the user, to fold the internal and the external functions together. This is faster than folding each function at a time.
3. Use block-scoped variables to prohibit data access
If a user has a large codebase, a slight change will have a large impact. The block-scoped variables allow developers to avoid the bugs that come as a result of accidental modifications on data. The block-scoped variables localize whatever impact the changes may have. Though block scopes allow a developer to reuse variable names, this is not their primary function. The real advantage is when they block any access to the internal data. They help you develop a safety net that helps you to ignore all internal variables in case the bug affects the external variables.
4. Plan before you code
When did you last sit and plan how you would approach a certain project? What frameworks do you intend to use? How many browsers will your program support? You can easily get into a project and start working on it, only to realize when you are almost finished that you need to rewrite a portion of the code. Plan the libraries you need to use so you may avoid undue delays and bugs.
5. Make use of version control
Version control records any changes made to a file, or group of files, for some time. It allows many users to host assets, track changes, and edit the code. Some of the services that enable version control are GitHub, Assembla, and Bitbucket. If you need to develop the best modular code, use GitHub since it endorses social coding, which means users can see each other’s code on GitHub as they learn how to improve their work.
6. Undertake coding challenges
There are numerous resources online which are aimed at giving developers challenges on the languages they use daily. Most of the sites have a large community that is ready to help. You should not worry about getting stuck and being unable to work.