Many people came across the word “algorithm”. After all, life of people is closely connected with it. What it is? What are the ways to describe algorithms, types of algorithms? What are they needed for? This article will help to understand all this and put everything in its place.
Algorithm: concept, types, description methods
The term itself denotes an understandable and accurate sequence of simple steps that the contractor must go through in order to solve the task assigned to him. The word "algorithm" itself originates from the name of the famous oriental scientist and mathematician Al-Khwarizmi. It was he who formulated all the rules by which arithmetic operations are performed. At the very beginning, under this concept was understood only the rules relating to the main four arithmetic operations performed on numbers. And only then the concept began to be used to indicate the sequence of steps leading to the solution of the problem. In a computing process, data is the objects to which the algorithm is applied. When solving the calculation problem, the source data is converted to the result.
The process of developing the algorithm is very creative, despite its simplicity. If a person can compose it, then the technique is also capable of performing. And today it is not only a computer, but also telephones, tablets, terminals and even washing machines with coffee makers.
Upon request, you can find a lot of valuable information on the Internet, but it still needs to be gathered together. Therefore, everything necessary is indicated here.
What are the main properties of the algorithm?
1. Certainty. This property is also called determinism. It implies obtaining a calculation result, which is unambiguous when setting the initial data for calculations. This property gives the execution process a mechanical character. No additional information and instructions about the task are required. There should be nothing arbitrary.
2. Massiveness. This property assumes that the algorithm should be suitable for solving many problems of the same type. The initial information in this case can be selected from some area called the area of application.
3. Efficiency - a property indicating the presence of initial information for which, according to a given sequence of actions, the process must go through a finite number of steps, and then stop, giving the desired result.
4. Discreteness is when the computing process is divided into stages. And the possibility of their implementation is not in doubt. Here, each subsequent action is performed only if the previous one is completely completed.
Ways to describe algorithms that everyone understands
Algorithms must be formalized according to certain rules using specific means. The main methods for describing algorithms: with the help of words, formula-verbal, algorithmic, graphic and software.
The verbal form is a record in natural human language. It has received much less distribution, as it is too verbose. And there is no clarity in it. The description in words is not strictly formalized, and some of the prescriptions can be interpreted ambiguously.
The formal-verbal form is a little more convenient. Here, mathematical formulas are added to the words, which can both help and, conversely, confuse a person when reading. Other ways to describe algorithms are much more convenient.
Ways to describe algorithms for computer scientists
The algorithmic recording method is based on pseudo-code. This is a code that is similar in structure to a programming language, but the commands are in natural language, and there are also mathematical expressions. Pseudocode is a semi-formalized language. This method is already much clearer, especially for programmers.
The methods for describing the algorithms described above were completely formalized, after which the program form of writing was born. Here one of the many programming languages is used, on which the very sequence of steps for execution is written. The computer reads them in turn and executes the specified instructions, which ultimately leads to the final result.
Most Popular Description Method
The graphical method for describing algorithms gained the greatest popularity because of its visibility. It is also called a block diagram. What is a flowchart? This is a graphical representation of the algorithm diagram. Each step of the data processing process is depicted in the form of a geometric figure called a block. Each block has its own configuration, which depends on the type of operation performed. The name and list of characters, sizes and shapes, as well as the displayed functions are defined by standards. If we take all the basic ways of describing algorithms, then this is the most obvious.
Calculation processes
Methods for describing algorithms using flowcharts imply three main types of calculation processes: linear, branching, and cyclic.
Linear is such a process when each stage of solving a problem is performed in order.
Branching is a calculation process in which, depending on the initial or intermediate information, as well as on the results of checking logical conditions, the direction of movement depends.
A cyclic algorithm contains one or more than one cycle, that is, a computation section that is repeated many times. Cycles can be with a predetermined number of repetitions and with an indefinite. Depending on the compliance with any condition, the number of these repetitions is determined. Moreover, the condition can be checked at the very beginning of the cycle or at its end.
The methods for describing the algorithms are clear, but there are also rules that are presented to them.
Rules for creating algorithms
First: when developing an algorithm, you need to specify many objects to work with. A formalized representation of such objects is data. The algorithm starts working with a set of data called input, converting them into a result - output data. In this case, any methods for describing the algorithms can be used. The properties of the algorithms must be observed.
The second rule: in order for the algorithm to work, it needs memory. It contains input, intermediate and output. The memory itself is discrete, that is, consists of separate sections - cells. That cell that has a name is called a variable.
The third rule is discreteness. The whole algorithm should be built from separate operations, the number of which must be finite.
It should be noted that there is such a thing as an auxiliary algorithm, which was developed in advance, and then applied to the algorithmization of another task. It can also be called an auxiliary procedure.
Algorithm, concept, properties, description methods - without all this in the field of informatics anywhere. This is the basis on which all computer science rests.