Training future teachers of information science to develop logical thinking skills of senior schoolchildren at teaching software development

The general scheme of solving software development tasks includes:

1. The task assignment (setting input and output parameters).

2. The description of the algorithm (the development of a mathematical task algorithm (if needed), the verbal description of the algorithm with further flow-chart description).

3. Program development (the algorithm description with a programming language).

4. Quality assurance of the program (the development of tests to test the program).

5. The program applying.

Let's consider each component of this algorithm in detail on the example of one task.

Task 1. Calculate the area of the triangle by the known three sides

I. Formation of the problem. In order to compile and implement the algorithm for computing the area of the triangle on three sides, it is necessary to determine the input and output parameters in accordance with the given task condition and, if necessary, to elaborate the condition of the task: to determine which data are permissible; under what conditions it is possible to obtain admissible results, and in which - no; which results will be considered correct.

In this case, the input parameters will be the sides of the triangle a, b, c, the output - area S. Moreover, all (input and output) data should be positive, and necessarily must be the inequality of the triangle for each side: any side of the triangle is smaller for the sum of the other two.

It is clearly seen that at this stage, such thoughtful operations as analysis and synthesis, abstraction, as well as the ability to allocate essential properties of objects that promote the development of logical thinking develop well.

II. Description of the algorithm, which in turn is divided into two stages:

1) construction of a mathematical model of the problem, choice of method for solving a problem, etc.:

As is known from the course of mathematics, the area of the triangle by the known three sides is calculated by the formula of Geron:

At this stage, the ability to find the main connections and the relation of objects and phenomena of the surrounding reality develop, which is a prerequisite for the development of logical thinking.

2) description of the algorithm verbally and using a block diagram:

We compile a block diagram (see Fig. 2) according to the described verbal algorithm. At this stage, we are developing such skills as constructing an algorithm, without which the development of logical thinking is not possible.

After drawing up the flowchart, we proceed to the next stage.

III. Drafting of the program: writing a program in the programming language C ++ (to compile the program in a certain programming language, you need to have the necessary (basic) knowledge).

Fig. 1. The stages of training future teachers of Information Science to develop logical thinking of senior schoolchildren

Fig. 2. Block diagram of the problem solving algorithm 1

Such famous scientists as U. Dal & E. Deykstry & K. Hoor [1] consider it important to separate structural programming as methodology. Independently, they supported the cancellation of goto operator in programming and the improvement of the theory of programming language of general purpose. As a result, the methodology of step-by step program development was suggested. The given methodology implies developing from global to local, general-to-specific, i.e. jumping into algorithm top down.

While building an algorithm, there is a necessity to explain some of the complex actions. This explanation can be based on the situations from everyday life. For instance, instructing a child how to clean a room at the first time, it is essential to explain how to do it, i.e. how to scrub, to dust, to fill a bucket with water and so on. After, there will be no need to explain it again, since a child has learned “chore algorithm”.

Taking into consideration all the mentioned above, it is possible to conclude, that every single task is a specific command for the executors, in case they know the algorithm of its performing. Applying this method leads to an algorithm which consists of simple commands. These commands can be either understood by the executor, or it can be inferred, that the selected executor is not able to solve this task. An example of it can be the explanation to a child how the plane is constructed, therefore, such task will be impossible to solve.

The proposed approach to develop algorithms is called the method of step-by-step detalization top down [2]. Here, every operation will be represented by the only one among three types of basic algorithm structures. They are: linear (following means that the operations are performed sequentially, one by one), branching (the specific operation execution depending on the condition) and repetition (a cycle makes repetition of the certain action many times). The level of detalization in the given case depends on knowledge, abilities and skills of an executor. professional training teacher computer science

Let us consider the simplest algorithm of a person crossing the street. Every child seems to be familiar with this this command since childhood due to the fact, that the parents have explained the traffic rules many times. These rules have become for a child a certain algorithm: if one has to cross the street, it is necessary to look at traffic lights and cross the street following these rules; if there is no traffic lights, the rules of crossing the street without traffic lights should be followed. Both cases require detalization of the given algorithm, i.e. explanation of main rules of crossing the street with traffic lights or without them.

But there are many other cases, when the given situation is constantly complicated with non-stop sequence of questions which are difficult to understand, that is why it requires using subtasks of an algorithm. These subtasks are called auxiliary tasks. They appear at splitting a complex task into simple ones or when there is a need to repeat the same set of actions within one or different algorithms many times. The described method of successive detalization is the basis of technology of structural development and is widely used at applying such programming languages as Pascal, С, C++ and others.

Auxiliary algorithms are implemented in the form of subprograms while describing a computer program by high-level programming languages. The rules can be used when needed and sent to the call site. They are determined with the certain programming language. To make it comfortable, it is possible to combine the frequently used subprograms into library modules and if it is necessary to use them in some programs.

The given stage is presented in detail in works by author [2]. As a result, students can obtain the skills and abilities of top-down programming. It will also help them to set out their ideas clearly, consistently, being able to explain their answers which are the basis of logical thinking development.

ІІІ stage. The improvement of a development task solution by the time of algorithm execution

The skills and abilities to improve the algorithms of task solution by time are the main aspects of future teachers training to develop the logical thinking skills of senior schoolchildren. The usage of knowledge in mathematics is one of the promising ways to solve the given problem.

Finding solutions to tasks for the certain period of time (an algorithm execution time is limited) is an essential requirement at competitions. The site www.e- olymp.com can serve as an example. It is used at competitions of different levels. Every task in the list of assignments is limited with time.

It is recommended to find a stable task for the given task. The solution of the stable task will be much faster than the initial one. Therefore, the task is significantly simplified; the execution of the algorithm becomes faster. Similar approach to a software development task analysis will allow improving its solution algorithm by time.

The third stage demonstrates the students' level to improve task solution by mathematical tools (the abilities to formulate and select from alternative hypotheses, to simplify an algorithm by improving task solution in contrast to formal overlearning are developed). It definitely improves the development of logical thinking.

ІV stage. Solving creative software development tasks

Conclusions

Therefore, the suggested stages of future teachers training to develop logical thinking of senior schoolchildren allow teaching students how to develop logical thinking of children in their professional activity. It also will help to unlock their creativity. Every stage demonstrates forming elements required to develop logical thinking.