What is Imperative Programming?

The computer programming paradigm defines the style of programming, approach to solve problem and method of computer systems towards providing solutions use programming. There is a classification of programming paradigms into two broad paradigms i.e., imperative and declarative. This article is based on the introduction to imperative programming, its key features, its advantages and disadvantages.

What is Imperative Programming?

Programming paradigm which is based on steps or series of statements and provides variation in the state of the program at each step is called imperative programming. Imperative programming deals with performance of the program by specifying the sequence of commands where commands are executed sequentially and change the state of the program until the end result is achieved. In imperative programming, computer receives the series of commands in steps from program to achieve the result.

Features of Imperative Programing

There are some important key features which belongs to the imperative programming.

• Control Flow: Imperative programming is based on control structures, assignment variables and I/O (input/output) statements.
• Conditional Loops: Control flow has multiple control structures in the form of conditional loops (for, while and do-while), which help in controlling the flow of execution.
• State Variation: There is a mutable state of the program in imperative programming i.e., the state of the program has been manipulated on each call of the command.
• Smaller Tasks: Imperative programming does not deal with the end results of the program rather it performs smaller tasks and functions for task completion.

These features are also present in paradigms of object-oriented programming (OOP), procedural and structural programming which are mutually exclusive subdomains of imperative programming.

List of Imperative Programming Languages

There are multiple languages which can provide the paradigm of imperative programming. Programming languages which majorly able to implement imperative programming are Java, C, C++, C#, Ruby, Matlab, Python and R. It is important to note that any programming language is not specific to a single paradigm but also incorporates some other paradigms as well.

In above diagram, we can see programming languages which are able to perform imperative programming along with some other mutually exclusive paradigms.

Subdomains of Imperative Programming

There are different mutually exclusive domains of imperative programming i.e., procedural programming, structured programming, modular and OOP. However, it is also important to note that all of these programming paradigms are present as the subdomains of imperative programming to provide evolution and address some challenges but there are some differences as well from imperative programming. There are some differences between these paradigms.

First it needs to understand that imperative programming is an opposite paradigm to declarative programming. Therefore, its main comparison is with declarative programming. Please visit Imperative vs Declarative Programming for more details. Additionally, imperative programming follows the imperative style of performing complete functionality step-by-step. All of the subdomains of imperative programming are mutually exclusive and deals with the small blocks of code. These subordinates of imperative programming are as follows:

1. Structured Programming

Structured programming is an extension of imperative programming which uses the control structure through iteration and sequence for code organization by using block structures like for loop, do-while or while loop etc. However, structured programming provides more maintainability as well as readability of the program by avoiding GOTO statements.

2. Modular Programming

Modular Programming deals with block of codes named as modules which are re-used. These modules are compiled together to get the final result. Structured as well as modular programming deal with the division of code into smaller parts but structured programming performs this through control structures and modular programming through modules.

3. Procedural Programming

Procedural programming divides the entire task into the smaller functions. Code, which is structured and based on the functions, but not object-oriented is fall under the domain of procedural programming. In this programming paradigm, procedures defined by functions dominates over data and hence making it different from OOP.

4. Object-Oriented Programming

Object-Oriented Programming formalizes the functions into objects providing the improved reusability of code and encapsulation. OOP can be called as the structured programming in which code defines the procedure and objects defines the attributes. OOP acts as the subset of imperative programming with additional features of abstraction, encapsulation, inheritance and polymorphism.

Advantages of Imperative Programming

Below are some advantages of imperative programming.

• Imperative programming depends on defined instructions to achieve the final result from the program. Therefore, code can be easy to understand and straightforward.
• Order of performing operations is completely controlled by developer because of control flow in program execution.
• Bugs can be easily traced because program is assembled from block of codes to perform smaller tasks and based on step-by-step commands.
• Memory allocation and manipulation is directly linked in imperative programming. Therefore, imperative programming has efficient utilization of machine memory.

Disadvantages of Imperative Programming

Below are some disadvantages of imperative programming.

• Imperative programming has control flow. Additionally, variables change on each command. In large programs, both of the factors can increase the complexity in code.
• To maintain the imperative programming attributes, there are long series/steps of commands. Therefore, it causes difficulty in readability as well as maintainability of the code in the large programs.

Conclusion

Imperative programming is the paradigm which is based on providing the result by focusing on the step-by-step command with manipulated state. There are many programming languages which are based on this approach of programming such as C++, python, R and Java. Control flow which exists as the major feature, facilitates the imperative programming. There are further subdomains of imperative programming which facilitates challenges observed in the old conventional approach of it, but it is important to know that now a days any program and languages is not following a single paradigm but combined paradigms.