We explain what a computer algorithm is and what it is for. Characteristics and parts of an algorithm. Practical examples.

What is an algorithm?

In computing , an algorithm is a sequence of sequential instructions , thanks to which certain processes can be carried out and certain needs or decisions can be responded to. These are ordered and finite sets of steps that allow us to solve a problem or make a decision .

Algorithms have nothing to do with programming languages , since the same algorithm or flowchart can be represented in various programming languages , that is, it is an arrangement prior to programming .

Seen this way, a program is nothing more than a complex series of algorithms ordered and coded using a programming language for subsequent execution on a computer .

Algorithms are also frequent in mathematics and logic , and are the basis for the manufacture of user manuals, instruction booklets , etc. Its name comes from the Latin algoritmus and this surname from the Persian mathematician Al-Juarismi. One of the best-known algorithms in mathematics is the one attributed to Euclid, to obtain the greatest common divisor of two positive integers, or the so-called “Gauss method” to solve systems of linear equations.

See also: Variable

Parts of an algorithm

Every algorithm must consist of the following parts:

• Input or input. Entering the data that the algorithm needs to operate.
• Process . This is the formal logical operation that the algorithm will undertake with what is received from the input.
• Output or exit. The results obtained from the process on the input, once the execution of the algorithm has finished.

What is an algorithm for?

Put very simply, an algorithm is used to solve a problem step by step . It is a series of ordered and sequenced instructions to guide a specific process.

In Computer Science , however, algorithms constitute the skeleton of the processes that will later be coded and programmed to be carried out by the computer.

Types of algorithms

There are four types of algorithms in computing:

• Computational algorithms. An algorithm whose resolution depends on the calculation, and which can be developed by a calculator or computer without difficulties.
• Non-computational algorithms. Those that do not require computer processes to be solved, or whose steps are exclusive for resolution by a human being .
• Qualitative algorithms. It is an algorithm whose resolution does not involve numerical calculations, but rather logical and/or formal sequences.
• Quantitative algorithms. On the contrary, it is an algorithm that depends on mathematical calculations to find its resolution.

Algorithm characteristics

The algorithms have the following characteristics:

• Sequential. The algorithms operate in sequence, they must be processed one at a time.
• Precise. Algorithms must be precise in their approach to the topic, that is, they cannot be ambiguous or subjective.
• Organized. Algorithms must be set in the precise and exact sequence so that their reading makes sense and the problem is solved.
• Finite. Every sequence of algorithms must have a specific purpose; it cannot be extended to infinity.
• Concretes. Every algorithm must offer a result based on the functions it fulfills.
• Defined. The same algorithm given the same input elements must always give the same results.

Examples of algorithms

A couple of possible algorithm examples are:

Algorithm for choosing party shoes :

1. START
2. Enter the store and look for the men’s shoes section.
3. Take a pair of shoes.
4. Are they party shoes?

     YES: (go to step 5) – NO: (return to step 3)

5. Is there the right size?

     YES: (go to step 6) – NO: (return to step 3)

6. Is the price affordable?

     YES: (go to step 7) – NO: (return to step 3)

7. Buy the chosen pair of shoes.
8. END

Algorithm to calculate the area of ​​a right triangle :

• START
• Find the measurements of the base (b) and height (h)
• Multiply: base times height (bxh)
• Divide the result by 2 (bxh) / 2
• END