Virtually everything in our world is subject to whatever laws and regulations.Modern science does not stand still, so that the mass of humanity known formulas and algorithms, following which, it is possible to calculate and re-create a variety of activities and structures created by nature, and to realize the idea, invented by man.
In this article, we discuss the basic concepts of algorithm.
story of algorithms
algorithm - a concept that emerged in the XII century.The word "algorithm" is derived from the Latin name of the interpretation of the famous mathematician of the Middle East Mohammed Al Khwarizmi, who wrote the book "On the Indian account".This book describes how to write the natural numbers using Arabic numerals, and a description of the algorithm of actions column on such numbers.
In the XII century the book "On the Indian account" has been translated into Latin, then, and there was this definition.
interaction algorithm man and machine
Create algorithm requires creativity, so the new list of successive actions can only create a living being.But for the execution of existing instructions fantasy does not necessarily have to deal with that, even soulless machines.
excellent example of precise execution of a given instruction is an empty microwave oven, which continues to work despite the lack of food inside it.
subjects or objects that do not necessarily get to the heart of the algorithm is called a formal performer.A man can also be a formal performer, but in the case of non-profitability of a particular action of the thinking performer can do everything on his own.Therefore, the main performers are computers, microwave ovens, telephones and other equipment.The concept of the algorithm in computer science is the most important.Each algorithm is made with the expectation of a specific subject, with the allowed action.Those objects for which an entity may apply the instructions that make up among the performers.
Virtually everything in our world is subject to whatever laws and regulations.Modern science does not stand still, so that the mass of humanity known formulas and algorithms, following which, it is possible to calculate and re-create the set of actions and creations of nature and realize the ideas thought up by man.In this article, we discuss the basic concepts of algorithm.
What is an algorithm?
Most of the actions that we carry out during their lives, requires adherence to certain rules.On how a person has the right idea about what, how and in what order it should do depends on the quality and the result of its tasks.Since childhood, parents are trying to develop an algorithm in its Chad basic actions, such as: wake up, fill the bed, wash up and brush your teeth, do exercises, breakfast and so on. E., The list of which man all his life performing in the morning can also be considered a kind of algorithm.
algorithm - a concept that refers to a compilation of guidelines that must be met for a person to solve a particular problem.
Generally, the algorithm has many definitions, some researchers characterize it differently.
If the algorithm used by man every day, each with its own, and can vary depending on age and situations in which is a performer, then a set of actions to be performed to solve a mathematical problem or to use the equipment, one for all and alwaysunchanged.
There is a different concept of the algorithm are also different types of algorithms - for example, for a person who pursues any purpose, and for technology.
In this age of information technology people routinely perform a set of instructions created by others before them, because the technique requires using the precise execution of a number of actions.Therefore, the main task of teachers in schools - to teach children to use algorithms to quickly grasp and change the existing rules in line with the current situation.The structure of the algorithm is one of those concepts that is studied in class of Mathematics and Informatics at each school.
basic properties of the algorithm
1. Resolution (sequence of individual actions) - any algorithm should be presented as a series of simple steps, each of which should begin after the completion of the previous one.
2. Certainty - every action of the algorithm should be as simple and clear to the contractor no questions and had no freedom of action.
3. Effectiveness - description of the algorithm must be clear and complete, in order to follow all the instructions the problem reached the logical end.
4. Mass - the algorithm must be applied to a whole class of problems that can be solved only by changing the numbers in the algorithm.Although it is believed that the last paragraph does not apply to algorithms, and all mathematical methods in general.
Often in schools to give children a clear description of algorithms, teachers cite the example of cooking cookbook, making prescription drugs, or soap making process is based on the master class.However, given the second property of the algorithm, which states that each point of the algorithm should be so clear that it can perform absolutely anyone, even the car, it can be concluded that any process that requires displays at least some fancy algorithmIt can not be named.A cooking and crafts require certain skills and a well-developed imagination.
There are different types of algorithms, but there are three main.
Cyclic algorithm
In this type, some points are repeated several times.List of actions that must be repeated to achieve the goal, the algorithm is called the body.
iteration of the loop - is the fulfillment of all the items included in the body of the loop.
part of the cycle that continuously performed a number of times, called cycle with a fixed number of iterations.
Those parts of the cycle, the repetition frequency of which depends on a number of conditions, called uncertain.
The simplest kind of cycle - is fixed.
There are two types of cyclic algorithms:
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cycle with precondition.In this case, the body of the loop checks its condition before it will be executed.
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cycle with postcondition.In the cycle with postcondition test conditions occurs after the end of the loop.
Linear types of algorithms
instructions such schemes are executed once in the order in which they are presented.For example, a linear algorithm can be considered as the process of making the bed, or brushing teeth.Also refer to this type of mathematical examples, where there are only the operations of addition and subtraction.
branching algorithm
The branching type have several options, some of them will be applied, depending on the conditions.
example.Question: "The rain is falling?"Possible answers: "Yes" or "No".If "yes" - the umbrella open when "no" - put an umbrella in the bag.
auxiliary algorithms
auxiliary algorithms can be used in other algorithms by specifying only its name.
terms used in the algorithms
Conditions is between the words "if" and "then."
For example, if you know English, press one.The proposal is part of the condition of the phrase "you know the English language."
data - information that bear some meaning and presented in such a way that they can be transferred and used for the algorithm.
algorithmic process - the task of the algorithm with specific data.
structure algorithm
algorithm can have a different structure.To describe the algorithm, the concept of which depends on its structure, you can use a number of different ways, such as verbal, graphic, using specially developed algorithmic language.
Which methods will be used, depends on several factors: the complexity of the problem, how you need to refine the process of solving the problem, and so on. D.
Graphic version of algorithm
graphics algorithms - a concept implies a decomposition actionto be performed for a specific task, for certain geometric shapes.
graphic scheme portrayed not as horrible.In order to be able to understand anyone used most often flowcharts and Nassi-Shneiderman strukturogrammy.
also flowcharts depicted in accordance with GOST 19701-90, GOST and 19.003-80.
graphic shapes used in the algorithm are divided into:
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Main. main image used to refer to operations necessary for data processing in solving the problem.
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Auxiliary.Auxiliary image need to refer to the individual, not the most important, element of the solution.
in graphics algorithms geometric shapes used to refer to the data is called a block.
All units are in the sequence of "top-down" and "left" - this is the correct direction of flow.When the correct sequence of lines interconnecting the blocks, do not indicate the direction.In other cases, the direction of the lines is indicated by arrows.
have proper algorithm scheme should not be more than one exit from the processing units and at least two outputs of the units responsible for logical operations and check the conditions.
How to construct an algorithm?
structure of the algorithm, as stated above, must be built in accordance with GOST, otherwise it will not be clear and accessible to others.
General procedure for recording includes the following items:
name by which it will be clear what can be achieved with the help of this scheme.
Each algorithm must be clearly marked beginning and end.
have algorithms must be clearly described in all the data, both input and output.
In drawing algorithm should be noted the actions that will make the necessary steps to solve the problem over the selected data.A typical form of algorithm:
- schema name.
- data.
- Home.
- Team.
- End.
proper construction of the scheme will greatly ease the calculation algorithms.
Geometric figures responsible for the different steps in the algorithm
horizontally arranged oval - the beginning and the end (the completion of the sign).
horizontally positioned rectangle - calculation or other actions (the sign of).
horizontally arranged parallelogram - input or output (character data).
horizontally arranged diamond - test conditions (the sign of the decision).
elongated, horizontally oriented hexagon - modification (character development).
Models algorithms presented in the figure below.
Formula-verbally version of algorithm development.
Formula-verbally algorithms written in any form, on the professional language of the region, to which the task.Description of actions carried out in this way by means of words and formulas.
concept of the algorithm in computer
in the computer field everything is based on algorithms.Without clear guidelines, introduced in the form of a special code that will not work, no equipment or software.In science lessons the students are trying to give the basic concepts of algorithms to learn to use them and create them yourself.
Creation and use of algorithms in computer science - the process more creative than, for example, the execution of instructions to solve the problem in mathematics.
There is also a special program of "algorithm" that helps people, ignorant of programming and create their own programs.This resource can become an indispensable tool for those who make their first steps in computer science and want to create their own games or any other program.
On the other hand, any program - algorithm.But if the algorithm carries only the actions that should be performed by inserting the data, the program already bears complete data.Another difference - is that the program can be patented and is privately owned, and the algorithm is not.Algorithm - a concept broader than the program.
Conclusion In this article, we discussed the concept of the algorithm and its types, learn how to write graphical schemes.
