TOPIC: "BRANCHING AND SEQUENTIAL DETAILS OF THE ALGORITHM"

Lesson Objectives:

Educational:

1. introduce students to the branching team.

2.show an example of a problem with two-step detailing.

Educational:

education of information culture, attention, accuracy, perseverance.

Developing:

1.development of self-control;

2.development of cognitive interests

Lesson type: combined

Type of lesson: lesson of explanation and primary consolidation of the material

Equipment: board, computers, projector

Textbook: Semakin "Informatics and ICT" Grade 9

Lesson plan:

Organizational moment, checking homework.

Explanation of new material.

Practical part.

Summing up the lesson.

Homework.

During the classes

Teacher activity

Student activities

Hello guys! Have a seat! Today we will study the branching algorithm.

Checking homework

Branch command

Let's get acquainted with another GRIS team. It is called the branch command. The format of the branch command is:

If<условие>
That<серия 1>
otherwise<серия 2>
sq.

The service word kv denotes the end of a branch.

As before, the GRIS can only check two conditions: “is there an edge ahead?” or “there is no end ahead?”.<Серия>is one or more consecutive commands. If<условие>is true, then<серия 1>, otherwise -<серия 2>.

Let's draw a block diagram.

Such branching is called complete.

Incomplete form of branching

In some cases, an incomplete form of the branch command is used

For example:

if the edge is ahead
then turn
sq.

Block diagram:

An incomplete branch command has the following format:

If<условие>
That<серия>
sq.

Here<серия>is performed if<условие>fair.

Let's make a relatively complex about the gram for GRIS. In this example, you will see that the use of the method of progressive detail makes it easier to solve some "puzzle" problems.

An example of a problem with two-step detailing

Task 6. Construct an ornament consisting of squares located along the edge of the field. The initial position of the HRIS is in the upper left corner, south direction.

Let's call the procedure that draws a chain of squares from edge to edge of the field a ROW. The procedure that draws one square is called SQUARE. First, write the main

Ornament program
early
make a ROW
turn
make a ROW
turn
make a ROW
turn
make a ROW
con

Now let's write the procedures SERIES and SQUARE:

In the SERIES procedure, the cycle body contains an incomplete branch. The structure of such an algorithm can be called as follows: a loop with nested branching.

ROW procedures.

Compiling this program required two steps to refine the algorithm, which were performed in the following sequence:

Now you know all the commands for controlling the graphical executor. They can be divided into three groups: simple commands; procedure call command; structural commands. The third group includes loop and branch commands.

Annex 1.

Let's move on to the practical part of our lesson.

Upload file C_1 level

Develop an algorithm for moving from point A to point B in a straight line with drawing a trace. The distance from A to B is not known in advance. But it is known for sure that there is a wall behind point B at a distance of one cell from it. Use this wall to complete the movement exactly at point B: jumping forward, check if there is a wall ahead and, if there is no wall, then go back and leave a trail.

Upload file C_2 level

Develop an algorithm for moving the performer from point A to point B, overcoming three pairs of "jumping" walls that appear on the way. The trail must be visible. Use the procedure to overcome one pair of walls.

Upload file C_3 level

Appendix 2

Annex 3

Appendix 4

Summing up the lesson, putting marks.

Homework item 31,

Annex 1.

Appendix 2

Annex 3

Appendix 4

| Lesson planning and lesson materials | 9th grade | Lesson planning for the school year | branching

Lessons 16 - 19
branching
Using two-step drill down
(§ 7. Branching and sequential refinement of the algorithm)
Using the Sequential Detailing Method to Build an Algorithm
Using Branches

branching

Branch command

Let's get acquainted with another GRIS team. It is called branch command. The format of the branch command is:

If <условие>

That <серия 1>

otherwise <серия 2>

Official word sq. marks the end of a branch. As before, the GRIS can only check two conditions: “is there an edge ahead?” or “there is no end ahead?”.<серия>is one or more consecutive commands. If<условие>is true, then<серия 1>, otherwise -<серия 2>. Such branching is called complete. An example is shown in fig. 1.11.

Rice. 1.11. Full branch flowchart

Incomplete form of the branch command

In some cases, it is used incomplete form branching commands (Fig. 1.12). For example:

If edge ahead

That turn

Rice. 1.12. Block diagram of incomplete branching

An incomplete form of the branch command:

If <условие>

That<серия>

Here<серия>is performed if<условие>is true, otherwise, the transition to the next command of the algorithm after the branch takes place.

Let's compose the last, relatively complex program for the GRIS. In this example, you will see that the use of the method of progressive detail makes it easier to solve some "puzzle" problems.

Lesson 32 1 hour).

The purpose of the lesson: the use of programming technology - the method of step-by-step detailing, the development of subroutines.

Approximate course of the lesson: This lesson can be considered as some kind of summary of the technology of procedural programming, since when solving problems with subroutines, it was the method of step-by-step detailing that was used. Discuss with students the features of developing rather complex software, the need to divide the task into subtasks, the possibility (or even the need) to solve these subtasks by different performers, the requirements for such solutions.

As an example, we can analyze the example presented in the textbook, while simulating the work of the program development team: discuss the general plan of the algorithm, draw up a program, and instruct students to develop subroutine texts, compare the solutions obtained. Be sure to pay attention to the necessity and importance (!) of the program testing process.

Summarize the lesson by discussing the system of basic concepts, questions after the paragraph.

Homework. §2.2.11, drill down the program for the problem: Create two one-dimensional arrays of size N and M using a random number generator. Insert the minimum element of the first array after the minimum element of the second array (if there are several minimum elements, then insert after the first of them).

Lesson 33 1 hour).

The purpose of the lesson: systematization of knowledge and skills in the development of subroutines and the application of programming technology - the method of step-by-step detailing.

Approximate course of the lesson:

disassemble homework. Find out how the students reasoned when dividing the task into subtasks, which subprograms the students used to compile the program. The solution might be:

program Home_Work;

type mas= arrayof integer;

var A, B:mas;

i, k,N, M:integer;

procedure Create( var X:mas; N: integer);

var i:integer;

for i:=1 to N do X[i]:=Random(100)-50;

procedure Print(X:mas; N: integer);

var i:integer;

writeln("Array:");

for i:=1 to N do

function Nom_Min(X:mas; N: integer):integer;

var i, N_Min:integer;

for i:=2 to N do

if X[i]

Then N_Min:=i;

Writeln("Enter the number of elements in array 1");

Writeln("Enter the number of elements in array 2");

k:=Nom_min(B, M);

(inserting the minimum element of array A after the minimum element of array B:)

For i:=M downto k+1 do

B:=B[i]; (shifted the elements of array B to the right by 1 position)

B:=A; (immediate insertion)

Then you can solve small problems in pairs, while students must develop a common algorithm, distribute responsibilities for compiling subprograms, compile and debug, and test the program. For example:

1) Create two one-dimensional arrays of different sizes. Find elements that belong to both the first and second array.

2) Create two one-dimensional arrays of different sizes. Find elements that are in the first array and not in the second array.

3) Create two one-dimensional arrays of different sizes. Find elements that are in the second array and not in the first.

4) Create two one-dimensional arrays of different sizes. Find the maximum values ​​in each array. Sort the array with the largest element in descending order.

Summarize the lesson, let the students share their impressions of the work.

Lesson plan (lesson) as a document that is a project of a specific lesson (based on an example in the disciplines of the profile of the specialty direction)

At its core, the lesson, as the main form of organizing learning in the class-lesson system, involves its planning as a prerequisite for effectiveness.

According to I.P. Podlasom, the formula for the effectiveness of a lesson includes two components: the thoroughness of its preparation and the skill of conducting it. Lesson preparation - the development of a set of measures for organizing the educational process, which include: diagnostics, forecasting, planning. And the skill of conducting, as a rule, is associated with the experience of the teacher.

As a rule, in order to enhance these two aspects in the effectiveness of conducting classes, young teachers in an educational institution are required to develop not only a lesson plan, but its outline plan or a detailed lesson plan to ensure its detailed planning and preparation.

The lesson plan is traditionally compiled in the TVET system, in many SSE institutions. Currently, there are no normatively approved requirements at the republican level on the obligatory preparation of lesson plans (classes) by teachers. However, as can be seen from the previous explanations, their preparation for the classroom system is recommended. Educational institutions, within the framework of the implementation of the education quality management system, can adopt their own standards for the need to reflect the results of constructing a teacher's lesson in the document "Lesson Plan" and even its form.

Lesson plan (lesson) - a document that is a project of a specific lesson, developed by a teacher for its implementation and reflecting its structure and main elements. The lesson plan includes the definition of the ultimate goals (tasks) of the lesson, its structure (course), a list of the main actions of the teacher and students to master the content of the educational material. An example form (fig. 21.1) can be used to draw up a lesson plan, which presents the main elements for describing the content of the lesson. When designing a lesson, each teacher enters the necessary (justified) information into the document being developed, for example, the name of the topic of the program, the formulation of the methodological goal of the lesson, the type of lesson, a description of the material and technical equipment, etc.

LESSON PLAN

Topic of the lesson program __________________________________ (number of hours)

Topic of the lesson ___________________________________________ (number of hours)

Lesson Objectives:

educational _________________________

educational _____________________

developing ________________________

Course (stages) of the lesson

Teacher's signature

Rice. 21.1. Sample lesson plan form (classes)

When preparing a lesson plan, it is difficult to give a clear recommendation for detailing the description of its content. We believe that it is necessary to describe the structure of the lesson to a degree that is understandable to other teachers and distinguishes it from other classes.

The course of the lesson is described by the teacher in accordance with its structure (the structure depends on the type of lesson, the type depends on the didactic goal). In this case, you can use their exemplary traditional structure, given in tab. 14.2.

The description of the stages of the lesson can be conducted through rubrication ( adj. 28, 29, 30, 31, 32, 33, 36 ) or in a technological map - a table that has strictly defined structural parts that characterize the educational process (Appendix 34). Its use when developing a lesson plan is optional. A description of the lesson plans in the form of a technological map can be found at the link: Methodology of the modern lesson: Methodological recommendations on the methodology of the modern lesson / Comp.: Zhuravkova T.K., Skomorokhova O.M., Skuratovich S.V. / Educational and Methodological Center for Vocational Education of the Department of Education of the Mogilev Regional Executive Committee. - Mogilev, 2007. - http://www.mgpl1.mogilev.by/methodist1.html.

The document “Lesson Plan” is drawn up with the fulfillment of the basic requirements of office work (Instruction on office work in state bodies and organizations of the Republic of Belarus, approved by the Decree of the Ministry of Justice of the Republic of Belarus dated January 19, 2009 No. 4 (as amended and supplemented)).

The plan of an open lesson is approved by the deputy head of the educational institution.

The lesson plan usually also indicates its date, number according to the thematic (calendar-thematic) plan, group number, specialty, qualification for which it is held. Any information is given not in order to increase its volume, and therefore reduce the efficiency of perception of its description, but to detail the necessary elements. For example, the name of the specialty is necessary if the discipline is read with different content for different specialties, therefore the teacher cannot confuse the lesson plans for them.

The objectives of the lesson can be set from different positions (see. section 23). If the teacher has chosen the option of setting three goals for the lesson (training, education and development or teaching, educational and developing), they should all be set from the same position. Another variant of goal-setting is possible: setting the didactic goal and objectives of the lesson as its parts. In this case, at least three tasks are formulated (teaching, educational, developing). Teachers who set goals from the position of a teacher usually also bring the results of the lesson in order to describe the specific expected activity of students and, accordingly, provide tasks for them to master it and evaluation criteria.

The lesson plan, if its form is not approved, has no restrictions on the volume and detail of the description of the content of the lesson. However, the teacher compiles this document both for verification by methodological services and for rationalizing their own activities, which is most important. He should help the teacher as much as possible in the conduct of the lesson. So, the teacher should be comfortable using it.

For a competent description of the lesson, it is necessary to indicate its type, since its structure depends on it. When designing a lesson, the teacher predicts the time spent on each of its elements. Time can be shown for each step in the lesson plan.

The description of the stages of the lesson is supplemented by the teaching methods that the teacher plans to use, the forms of teaching, and teaching aids. If necessary, these tools are detailed (described) directly in the lesson plan (for example, planned questions may be indicated to update knowledge, etc.). However, there are more detailed forms for describing the content and organization of the lesson.

The lesson plan indicates the necessary logistics or TCO, homework. The lesson plan may be accompanied by the necessary didactic materials (standard answers to tasks of a closed test, task cards, etc.), evaluation criteria.

It must be remembered that there are several forms of describing the results of designing a lesson: lesson plan, outline plan, detailed outline plan, non-traditional lesson scenario, methodological development. In this enumeration, the forms of describing the lesson are ranked on the basis of increasing detail of the description. Although the framework between them is rather arbitrary (if their form is not documented).

Lesson summary - a detailed description of the lesson. It does not fix not only the structure of the lesson, but also the educational material. A detailed outline plan implies a detailed (complete in comparison with the abstract) description of the lesson.

Methodical development is a set of all materials that provide a lesson. It contains a lesson plan or outline. The text provides an explanation of many positions of the methodology for conducting a lesson, methodological support for a lesson (or a series of lessons).

Related issues: MP - 5 , 6 , 7 , 8 , 9 , 10 , 14 , 20 , 22 , 23 , 35 ; P - 18 , 19 .

Topic: "Incremental refinement method"
Learning goal: To repeat with students the stages of solving problems on a computer: formulation, algorithm, method of a mathematical model, program, analysis of results. Introduce the concept of stepwise refinement method.
Having developed the goal: To develop logical thinking, memory, interest in the subject. Ensuring a strong and conscious mastery of the basics of computer science by students.
Bring up the goal: Culture of behavior, communication. Education in students of information culture. Preparing students for an active full life and work in the information society.
During the classes:
1. Org moment
2. The stage of setting the goal of the lesson
3. Poll d / z
Stages of solving problems on a computer: setting, algorithm, method of mathematical model, program, analysis of results.
Test
1. A clearly formulated sequence of rules describing this process is
a) block diagram
b) algorithm *
c) one of the properties of the algorithm
2. Properties of the algorithm
a) accuracy, certainty, effectiveness
b) clarity, understandability, effectiveness
c) discreteness, certainty, mass character, effectiveness *
3. The developed algorithm can be fixed in several ways
a) graphic
b) drawing up equations, rules, formulas
c) verbal description, block diagram, in algorithmic language *
4. The stage of information processing is depicted
a) a rectangle *
b) rhombus
c) oval
5. Checking conditions is depicted
a) a rectangle
b) rhombus *
c) a square
6. In a figure similar to an oval, we write
a) input, output*
b) formula
c) beginning, end
7. We write the input of the initial data and the output of the result in ...
a) parallelogram *
b) square
c) rhombus
8. Which of the documents are algorithms?
a) Spelling rule for prefixes ending in z, s
b) TV program guide
c) Cooking recipe*
d) Instructions for assembling a cabinet sold disassembled *
9. In what cases does the sentence end correctly: An algorithm is
a) the final sequence of actions leading to the desired result for any valid initial data *
b) instructions to perform actions
c) a finite set of commands understandable to some executor, the execution of which leads to a unique solution of the problem
d) program in machine codes
10. The division of the algorithm into separate elementary actions is
a) Discreteness*
b) Certainty
c) mass character
d) Determination
11. Which of the documents are algorithms?
A) Catalog of books in the library
B) Procedure for dialing an international telephone number*
C) Recipe for making glue*
D) Wall calendar for the current year

Check: Evaluation criterion: 11 "+" -5, 9 "+" -4, 7 "+" -3, 5 "+" -2

4. Explanation of the new topic:
The success of any activity depends on careful planning. And the more difficult the task, the more important the ability to plan your actions. The main thing in this case will always be a clear definition of the final results, then the definition of intermediate results, without which it is impossible to achieve the goals.
This approach turns out to be the only possible one when compiling complex algorithms and large programs for solving problems using a computer. This method is called step-by-step detailing of algorithms and programs. With step-by-step detailing, algorithms are written as a set of auxiliary algorithms that solve auxiliary subtasks, and each of them requires obtaining certain intermediate results.
Having developed the main algorithm, one can proceed to the development of “second level” algorithms, which in turn may require further detailing. Thus, the main algorithm is a plan of action that must be completed to achieve the goal, and the essence of each action is deciphered in the corresponding auxiliary algorithm.
Using step-by-step detailing to describe algorithms allows you to clearly, clearly and understandably describe how to solve problems.
The method of step-by-step detailing facilitates the compilation of algorithms, since allows you to solve the problem in parts and use as auxiliary algorithms problems that have not yet been solved. This structure is called top-down programming.
Let's consider the problem and compose an algorithm using the method of step-by-step detailing.
1. There are 2 jugs with a capacity of 3L and 8L. Artist Jin can draw water from the river into each jug, pour water out of it and determine whether the water in the jug is filled to the top. Make up an algorithm, by executing which Jin will draw 7 liters from the river. water.
2. The performer is able to replace one letter in a word, and from a meaningful word a meaningful word should turn out again. Write a transformation algorithm:
a) the words GARDEN to the word CAT;
b) the words FLY into the word ELEPHANT.

5. The stage of staging D / s: read the summary, come up with several short (no more than 15 commands) programs with errors, so that in the next lesson they can be debugged by your neighbor on the desk. Having previously reported for what purpose you compiled these programs.

6. The stage of summing up the lesson.