# Algorithm vs Program: What is the Priori Analysis and Posteriori Testing

Learn the difference between an algorithm and a program and the terms Priori Analysis and Posteriori Testing.

## Table of Content

In this lesson, we will briefly go over the difference between an algorithm and a program.

We will also look at two terms used in algorithms and programs called Priori Analysis and Posteriori Testing.

To understand the difference between an algorithm and a program, we should mention the two main phases of software development.

They are the design phase and implementation phase.

When you are working on a software project, the first and most important step is to design the software you intend to build.

Designing the software ensures you get all the crucial parts of your project and idea sorted before you implement it.

The design phase usually includes writing well-detailed specifications, graphical representation of the User Interface (UI), mockups, prototypes, and more to help explain the idea more clearly.

All the activities in the design phase help to further elaborate the step-by-step procedure of the software being developed.

Therefore, the difference between an algorithm and a program is that algorithms are the step-by-step procedure of a project specified during the design phase while a program is the result of the project from the implementation phase of the development.

## 5 Differences Between an Algorithm and a Program

Here are five differences between an algorithm and a program:

1. An algorithm is a step-by-step procedure of a software development project, while a program is an actual project being implemented.
2. An algorithm is usually created during the design phase, while a program is created during the implementation phase.
3. An algorithm requires having domain knowledge and understanding of the project e.g. knowledge of API specification, UI expertise, etc. while a program requires having knowledge of transferring specification to machine codes, the development tools, languages, and more. e.g. knowledge of software development.
4. Algorithms are usually written using a natural language e.g. English while a program is written using a programming language such as Java, Python
5. An algorithm is usually analyzed for time and space complexity, while a program usually undergoes testing for efficiency, effectiveness, and quality assurance.

## What is Priori Analysis?

Priori analysis is the analysis of an algorithm by studying it deeply to know how it works and to get the time and space complexity.

## What is Posteriori Testing?

Posteriori testing on the other hand is done on the program by executing the to check how the speed and performance in terms of how long it takes to run and the number of bytes consumed.

## What is the Difference Between Priori Analysis and Posteriori Testing?

The main difference between Priori Analysis and Posteriori Testing is that Priori Analysis is speed and performance evaluation done on algorithms by testing for time and space complexity, while posteriori testing is speed and performance evaluation done on programs by testing the time and bytes consumed.

For this reason, the difference simply follows the difference between an algorithm and a program.

Here is a table detailing the difference between Priori Analysis and Posteriori Testing.

Priori AnalysisPosteriori Testing
Performed on algorithmsPerformed on programs
Does not depend on any languageDepends on a language
Does not rely on the use of a computer hardware, can be done with pen and paperRequires the use of a computer hardware to implement it efficiently
Checks for time and space complexitiesChecks for time and bytes consumed

## Wrap Off

In this lesson, we went over the difference between an algorithm and a program.

We also looked at two terms used in algorithms and programs called Priori Analysis and Posteriori Testing, what they are, and their differences.

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