Key Difference – Structured vs Unstructured Programming
A computer program is a set of instructions for a computer to perform a task which is written using a programming language. A programming paradigm can categorize the programming language depending on language features. Structured programming and Unstructured programming are two common programming paradigms. The key difference between Structured and Unstructured programming is that Structured programming allows the programmer to divide the whole program into modules or functions and in Unstructured programming, the code is written as one block.
CONTENTS
1. Overview and Key Difference
2. What is Structured Programming
3. What is Unstructured Programming
4. Similarities Between Structured and Unstructured Programming
5. Side by Side Comparison – Structured vs Unstructured Programming in Tabular Form
6. Summary
What is Structured Programming?
In Structured Programming, the code is divided into functions or modules. It is also known as modular programming. Modules or functions are a set of statements which performs a sub task. As each task is a separate module, it is easy for the programmer to test and debug. It is also easy to do modifications without changing the whole program. When changing the code, the programmer has to concentrate only on the specific module. C language and Pascal are some examples of Structural Programming languages.
Figure 01: Functions using C program
A programming language like C can use user-defined functions. Functions are called by the main program. Variables in the functions are called local variables, and global variables can be accessed by all the functions. Structured programming languages also use selections (if/ else) and iterations (for /do, while). The program in Figure 01 shows the functions using Structured programming language C. Program was written and executed using Code Blocks Development Environment.
What is Unstructured Programming?
In Unstructured Programming, the code is written as a single whole block. The whole program is taken as a single unit. It is harder to do changes in the program. This paradigm was used in earlier versions of BASIC, COBOL, and FORTRAN. Unstructured programming languages have a limited number of data types like numbers, arrays, strings.
What is the Similarity Between Structured and Unstructured Programming?
- Both are programming paradigms.
What is the Difference Between Structured and Unstructured Programming?
Structured vs Unstructured Programming |
|
| Structured Programming is a programming paradigm which divides the code into modules or function. | Unstructured Programming is the paradigm in which the code is considered as one single block. |
| Readability | |
| Structured Programming based programs are easy to read. | Unstructured Programming based programs are hard to read. |
| Purpose | |
| Structured Programming is to make the code more efficient and easier to understand. | Unstructured programming is just to program to solve the problem. It does not create a logical structure. |
| Complexity | |
| Structured Programming is easier because of modules. | Unstructured programming is harder when comparing with the structured programming. |
| Application | |
| Structured programming can be used for small and medium scale projects. | Unstructured programming is not applicable for medium and complex projects. |
| Modification | |
| It is easy to do changes in Structured Programming. | It is hard to do modifications in Unstructured Programming. |
| Data Types | |
| Structured programming uses many data types. | Unstructured programming has a limited number of data types. |
| Code Duplication | |
| Structured programming avoids code duplication. | Unstructured programming can have code duplication. |
| Testing and Debug | |
| It is easy to do testing and debugging in Structured Programming. | It is hard to do testing and debugging in Unstructured programming. |
Summary – Structured vs Unstructured Programming
Structured and Unstructured programming are two paradigms in programming. The difference between Structured and Unstructured programming is that Structured programming languages allow the programmer to divide the whole program into modules or functions and in Unstructured programming, the program is written as one single block. Structured programming languages are the modern languages, and unstructured languages are the earliest versions of programming languages.
Download the PDF Version of Structured vs Unstructured Programming
You can download PDF version of this article and use it for offline purposes as per citation note. Please download PDF here Difference Between Structured and Unstructured Programming
Reference:
1.“Programming paradigm.” Wikipedia, Wikimedia Foundation, 14 Dec. 2017. Available here
2.“Structured programming.” Wikipedia, Wikimedia Foundation, 15 Dec. 2017. Available here
3.Vritika. “Difference between Structured and Unstructured Programming Language.” Vritika, 10 Aug. 2015. Available here