Procedural Programming | What should you know

A programming paradigm is defined as a “style or way of programming” or an approach to solving a programming problem. They are used to classify programming languages on the basis of their features. Among the four main programming paradigms is the procedural programming paradigm.

Procedural programming is derived from structured programming, which is further derived from the imperative programming paradigm.

Procedural programming paradigm is based on the concept of procedure call, i.e., calling a function in the program.

Procedures are simply series of steps that need to be executed. It uses a top-down approach, i.e., breaking down the system into parts to gain insights into it. Major procedural programming languages are COBOL, BASIC, Fortran, C, and Pascal.

Features of procedural programming

We explain the key features of procedural programs below:


Modularity means using or employing modules, i.e., chunks or parts. It means to divide the large problem into smaller modules to solve it easily. It involves dividing the functionality of the program into independent smaller parts, and each part can execute that specific function for which it was produced.

Modular design allows the whole task to be broken down into smaller executable chunks that can easily be converted into computer code. It is thus the decomposition of a program into smaller parts that are easier to understand, manipulate and manage. In structural programming, modular programming refers to the low-level code use of structured flow.

There are many advantages to code in a modular programming way. The major advantage is that the program is easier to work on. Also, it enables to call a piece of code repeatedly. Also, a single module can be executed separately from the other parts because it is an independent piece of the whole program.

In procedural programming, the concept of modularity means that in a large program, there are smaller pieces, with each piece doing one task. These modules or pieces do tasks one after another and then give the final result.

Predefined functions

A function is a method that can be called by its name in the program. Predefined functions are also called built-in functions. They are the set of subroutines that are used for specific functionalities.

These functions are normally already present in high-level programming languages such as Python and C++ but may also be loaded in the programming language from the registries or programming libraries.

They contrast with user-defined functions, which are the functions defined by the user and need to be loaded through a program, i.e., they are only present in that specific program, not anywhere else.

An example of a pre-defined function would be concat(), which allows concatenating the text of two strings into one new string. Another example could be sqrt() which takes the square root of any number passed to it as an argument. The sqrt() function is a predefined function because it is already built-in in python and does not need to be loaded manually.

They are quite useful because the user does not need to write a long line of code for a process and can use a function instead. Also, built-in functions do not need to be loaded, which makes them extra convenient.

Local variable

Variables in programming languages are storage spaces with specific names. Users can assign values to them. They are used to reference a stored value in a program.

Local variables or lexical variables are the variables that are defined within a specific method and can only be used/referenced in that specific method. So, their scope is local, and thus they cannot be used outside that specific method. If there are other methods in the program, they will not be aware of the local variable made in this method. If a local variable is called in another method, the program will give an error.

An example of a local variable can be:

function num(){

var x;


The variable x defined inside the function here can only be accessed within the function.

It does not have any value outside the function num(). So, it can be considered a local variable. Local variable only exists till the block of code in which it is defined executing. After the execution, it is automatically destroyed.

Local variables play an important role in procedural or modular programming because they do not have some side-effects that global variables pose in these types of programming.

Global Variable

A global variable, unlike a local variable, is defined outside of a function. Due to this reason, it can be used at any place in the program, i.e., its scope is the whole program, unlike a local variable, which has scope only inside the block of code where it was defined.

Global variables can be used anywhere or in any function in the program. Their values can be changed by any function in the program. The set of global variables which can be sued at any place in the program is called global environment. Global variables are mainly used to pass information between different sections of code that do not have any caller/callee relation, like signal handlers and concurrent threads.

In some programming languages, only global variables are available, while most of the programming languages allow one to choose between global and local variables. Some of these languages, such as Python and MATLAB, allow the declaration of a global variable anywhere in the program, even inside the function, by using the ‘global’ keyword. Some programming languages do not support global variables at all, notably some modular programming languages.

Parameter passing

Parameter passing is a mechanism in programming languages by which parameters are passed to procedures or functions. The parameter is not to be confused with argument. The argument is the actual value that is passed to the function that gets processed by the function, while the parameter is the value mentioned in the function while declaring it.

Parameters can be passed to a function in multiple methods. The four methods of parameter passing are mentioned and explained below:

  • Pass by value

Pass by value mode uses in-mode semantics. Using this method, any change made to the perimeter does not transmit to the caller. Modifications to the parameter are only reflected in the separate storage location, and the actual place where the function is called is not affected by it.

  • Pass by reference

This method uses in/out-mode semantics. Using this method, changes made to the parameter get transmitted back to the place where the function is called.

  • Pass by the name

In this type of parameter passing, the name of the variable is passed, which allows it to be accessed and updated.

  • Pass by value-result

This method uses in/out-mode semantics and is a combination of pass by value and pass by the result. By using this method, the value of the formal parameter is returned back to the actual parameter before the control shifts to the caller.

Procedural programming vs. object-oriented programming (OOP)

Procedural programming vs. object-oriented programming (OOP)
Source: SlideShare

Object oriented programming (OOP) is a widely used programming paradigm that uses “objects” to store data (in the form of fields or attributes) and code (in the form of procedures or methods). The programs designed in object-oriented programming are built with a top-down approach using the concept of objects that interact with the real world. Most of the popularly used programming languages such as C++, Python, and Java use multiple paradigms, including object-oriented programming paradigm.

Procedural programming significantly differs from object-oriented programming because the essence of procedural programming is functions, while OOP is primarily based on objects. Below are some main differences between these two programming paradigms (procedural programming vs oop):


The procedural-oriented programming paradigm is derived from the imperative programming model, while the OOP paradigm is closely associated with the declarative programming paradigm.

Primary focus

The procedural-oriented Programming paradigm is based on the concept of algorithms (a finite sequence of executable computer instructions). mainly dealing with data storage, manipulation, and management.

Working mechanism:

The primary method in procedural programming is to break down a large complex problem into its smaller chunks which are easy to understand, manipulate and manage. On the other hand, object-oriented programming (OOP) focuses more on the objects that are to be manipulated rather than the method or logic by which they are to be manipulated.


Procedural-oriented languages use a top-down approach which is dividing down a large complex problem into its smaller chunks that can each be studied individually. OOP uses a bottom-up approach which requires building a large and complex program from its smaller parts or chunks. The former breaks a large program into smaller parts, while the latter builds a large program from several small ones. The approach of these procedure-oriented and OOP in this regard is totally opposite to each other.

Program division

In the procedural programming paradigm, a program is divided into functions or blocks of code. The unit of programming in this paradigm is function. In object-oriented programming paradigm, the program is divided into different objects of classes, and the unit of programming is class.

Memory requirement:

Due to the data-oriented nature of OOP, the paradigm requires a lot of memory or space for working. On the other hand, the procedure-oriented programming paradigm requires very little memory for its work.


In procedure-oriented programming, the data members are always public because there is no access specifier in this paradigm. Object-oriented programming gives a choice to the user to select between public, private, or default members by its access specifiers. Due to the same reason, data hiding is not possible in the procedure-oriented programming paradigm, while object-oriented languages support data hiding.

Also, data in procedural-oriented programming languages move from function to function, while in object-oriented programming paradigm, it is hidden from any external functions. It means that the object-oriented programming paradigm is much more secure than the procedure-oriented programming paradigm.

Further features

The object-oriented programming paradigm uses features such as inheritance property and virtual function, while these features are not used in the procedure-oriented paradigm.

The procedural-oriented programming paradigm follows no overloading, while the object-oriented programming paradigm follows operator and function overloading.


The object-oriented programming paradigm provides extensibility and support for new datatypes while the procedural languages do not. This gives the object-oriented paradigm much more ease and flexibility to users. Objects are difficult to add in procedural-oriented programming languages, while objects such as data and functions can easily be added in an object-oriented programming paradigm.

Object-oriented programming also supports much more functionality, flexibility, and abstraction than the procedural programming paradigm. The abstraction in the procedural-oriented programming paradigm uses procedural abstraction, while the object-oriented programming paradigm uses class and object abstraction.

  Data storage

Data and associated behavior are kept in a single location in an object-oriented programming paradigm while they are viewed as different and kept in different locations in a procedural-oriented programming paradigm. The procedural-oriented programming paradigm does not support parallel programming, while the object-oriented programming model supports parallel programming.


Communication with code in the procedural-oriented programming paradigm occurs through calling the function in the program, while in object-oriented programming, objects communicate with each other by passing messages.

  Debugging and code reusage

The debugging process in procedural languages is very difficult and frustrating, while debugging is very easy in object-oriented languages. Also, object-oriented programming supports much easier reuse of cod than the procedural-oriented programming paradigm.


Due to the above-mentioned reasons, procedural-oriented programming languages offer very low productivity compares to OOP environments. It is far easier to work on a complex project in an object-oriented environment than in a procedural language.


Most of the procedural programming languages are used for theoretical problem solving, while the object-oriented model is more useful in real-world objects so is used in solving real-world problems.


Famous examples of languages that support a procedural-oriented programming paradigm are Haskell, C, Pascal, Fortran, and BASIC. Famous examples of languages that support OOP paradigm are C++, Python, and Java.

Advantages of Procedural Programming

  • As PP paradigm means step by step instructions or a logical sequence of code that tells the computer to perform a specific task, that’s why it’s easy for a programmer to track the program flow.
  • PP is excellent for general-purpose programming.
  • There is a large variety of books and online course material available on the internet that makes it easy to learn.
  • Its source code is portable and thus can be used to target a different CPU as well.
  • This programming paradigm requires less memory.
  • To code with PP is simple. Code can be reused in the program without the need to copy.

Disadvantages of Procedural Programming

  • Using PP, data is exposed to the whole program, making it less secure.
  • It is very difficult to relate to the PP paradigm with real-world problems.
  • It is difficult to identify the belonging of global data in a large program.
  • In PP, modification of global data requires the modification of functions using it.
  • Due to global data, maintaining and enhancing code is difficult in larger programs.
  • In PP, importance is given to the operation rather than data that may cause issues in data-sensitive cases.


In computer science, PP is easy to learn and implement. It’s easy for new programmers to start their journey with a procedural paradigm. It will certainly help to understand how the procedural languages works.

Due to its limitations, real-world applications are not using the PP paradigm.

To expose real-world problems, learners should have to learn other programming paradigms as well. This paradigm focuses more on what you are doing instead of how you are doing.

We also had a good analogy into object oriented programming vs procedural programming and understanding the difference in both paradigms

Popular Programming Paradigms: Let’s have a look at some MAJOR Programming Paradigms in detail:

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