The document discusses teaching methods and tools for presenting pseudocode language to students. It provides: - Keywords used in pseudocode like read, write, if, then, else, while, and for to define instructions. Algorithms start with "Algorithm name" and end with "Stop". - Examples of read-write instructions using keywords read and write to input and output data. - Exercises for students to practice using pseudocode keywords and instructions like reading numbers, writing outputs, and comparing values in if statements. - Discussion of theoretical concepts like assigning values, expressions, variables, and data types to introduce in pseudocode programming.

1. Teaching Method and
Flexible Tools
MATERIALS FOR STUDENTS
THE PRESENTATION OF THE PSEUDOCODE LANGUAGE
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2. Algorithms’ representation using a pseudocode language 1
The pseudocode language is a means to represent algorithms for problem solving. It is a
symbolic language generated by the natural language where there are rules characteristic to
programming languages.
The basic elements of the pseudocode are the key-words. They have a strict meaning and
are used in syntactical formulas which aim to describe the algorithms’ fundamental structures.
Thus, we can speak about a vocabulary of the pseudocode language. The key-words can be
classified as follows:
Key-words which define the types of data with which the algorithms operate : integer,
real, boolean, string
Key-words which are used to writhe instructions read, write, if, then, else, while, do,
repeat, until, for, end, stop
Consequently, any algorithm starts and finishes with the words Algorithm name,
respectively Stop.
PRE-PRIMARY SCHOOL
THEORETICAL APPROACH
READ-WRITE INSTRUCTIONS
They describe the operations of data reading and writing.
For data input we use the key-word Read.
Syntax:
Read list
Effect: Key- word read followed by the list of variables whose values will be read,
separated by a comma.
Example:
Read a, b
Respectively, for writing the results we use the key-word Write.
Syntax:
Write list
Effect: the key-word write followed by the list of variables whose values will be
displayed, separated by a comma.
Example:
Write the average
1
Livovschi, Leon, Georgescu, Horia – Sinteza şi analiza algoritmilor, Editura Ştiinţifică, Bucureşti, 1986

3. Observation: For better understanding, we will also write a message, in inverted
commas “ ” , separated by space by the exit data.
PRACTICE
Exercise 1
Read a number, then print the read number.
Read_write algorithm
Integer a
Read a
Write “read number ”, a
Stop
Exercise 2
What number must □ have for the equality to be true:
5 + □ =13
Indication: we will use the reverse operation to addition that is the substraction, to
find the unknown value, actually we will solve a number one degree equation, with an
unknown value.
The assigning algorithm
Integer x
x← 13 - 5
Write “x= ”, x
Stop
FIRST CLASS
THEORETICAL APPROACH
THE ASSIGNING INSTRUCTION
It describes the assigning operation in any algorithm
Syntax: v:=e or v ← e
Effect: The v variable will be assigned the value of the expression e.
This occurs over 2 stages:
1) It is calculated the value for the expression e
2) The v variable is assigned the value obtained in 1)
PRACTICE
Exercise 1
Read 2 integers a, b. Fiind aut which is the largest and display the value.
Algorithm
Integer a, b
Read a, b
if a>b then write it is larger ’,a
else write ’it is larger ’,b

4. end_if
Stop
Exercise 2
Read 2 integers a, b. Calculate their sum and display it.
The algorithm of the sum
Integer a, b
Read a, b
s←a+b;
write ’the sum is’,s
Stop
SECOND CLASS
THEORETICAL APPROACH:
An algorithm is a collection of symbols used in mathematics and logics, which, by a
succesion of operations solves an entire class of similar problems. The known data
of the problem which is to be coded in a programming language are called input
data. The results obtained after the problem solving are called exit data.
INPUT DATA ―‣ ALGORITHM ―‣ EXIT DATA
Many problems have other data, which are not known from the start thus they are
not considered input data. At the same time, these data are not as important as to be
written. However, they are useful in different stages of problem solving and algorithm
coding, they are absolutely necessary. That is why they are called intermediate or auxiliary
data.
PRACTICE
Exercise 1
Justin has two glasses: one with rasberry juice and one with coke, same capacity,
both full. Write, using an algorithm, the succesion of stages used by Justin to change
the content of the two glasses, without mixing them.
Indication:
We will code the glass with rasberry juice as variable a and the glass with coke as
variable b. To change the beverages we will use a third glass, empty glass, coded as
auxiliary.
The succesion of the steps is the following: the problem is similar with the following one.
o We pour in auxiliary empty glass the content of glass a
o We pour in glass a the content of glass b
o We pour in glass b the content of glass a

5. integer a, b, aux;
read a, b;
aux←a;
a←b;
b←aux;
write a, b
Stop
Exercise 2
In class 2nd A at the Theoretical Highschool Tudor Arghezi from Craiova, the
number of girls equals the double of boys. How many boys and how many girls if
the total is 24 pupils?
Indication:
We notice that if we code the number of girls as f and the number of boys as b we get
f=2*b. So, the class is formed by 1b+2b=3b. The operation of dividing the total number of pupils
by three will give the number of boys,that is 8. We double this value and we get the number of
girls , that is 16.
This algorithm can be used for any type of data, by assigning the corresponding values of
the problem to be solved.
integer b, f, t;
t←24;
b←t/3;
f←b*2;
write ’the number of boys is ’,b, ’ and the number of girls is ’,f
Stop
THIRD CLASS
THEORETICAL APPROACH
Expressions are a string which contains:
• A variable
• A variable operator a variable
• An expression operator an expression
• operator expression (for the operators such as – (5+3) )
Operators can be:
• the symbol ” – ” for substraction
• the symbol ” + ” for addition
• the symbol ” * ” for multiplication
• the symbol ” / ” for division

6. • the symbol ” % ” to get the rest of the division of the first value to the second one.
Example:
a % b = the rest of the division of a to b
a % 2 = the rest of the division of a to 2, which is 1 if a is an odd number or 0 if a is an even
number
a % 10 = the rest of the division of a to 10 , which is the last digit of a, the unit digit.
Observations:
1. the order of operations is similar to mathematics: first the multiplication and the division then
addition and substraction .
2. We can use brackets for more complex expressions, but only round ones.
PRACTICE
Exercise 1
At a maths competition the students are supposed to solve 40 problems. Each
correct answer gets 2 points, each wrong answer gets minus 0,5 points. Bonus points 20.
Alex solved 20 problems correctly but he was wrong about 12. How many points did he
score?
Indication:
We coded as rightnumber the number of correct answers and wrongnumber the number
or false answers. We calculated the scores separately, for right answers with the rightnumber
variable respectively the false answers with the wrongnumber variable. To get the final results,
we will add 20 bonus points to the rightnumber variable then we will substract the wrongnumber
variable.
This algorithm can be used for any values, provided they are assigned in the programme,
as the respective problem requests.
The algorithm of the competition
Integer a,b, sc, sp, sg
rightnumber←28
wrongnumber ←12
rightnumber ←28*2
wrongnumber ←12*0.5
totalnumber← rightnumber +20- wrongnumber
Write “Alex got =“, totalnumber
Stop
Exercise 2
Adrian and Cristian have 65 €, Cristian and Bob have 52 €, while Adrian and Bob
have 47 €. What sum does each of them have?
Indication:
We coded a Adrian’s sum, b Bob’s sum and c Cristian’s sum. We wrote the mathematical
relations given in the problem.
Step 1. a+c=65 (1)
Step 2. c+b=52 (2)

7. Step 3. a+b=47 (3)
Step 4. From (2) we substract (3) and we get:
c-a=5 (4), which in correlation with (1) gives c=35
Step 5. By substitution, from (2), we get b=17
Step 6. From (1) we get a=30
Step 7. Write a, b,c
FOURTH CLASS
THEORETICAL APPROACH
The data the algorithms operate with are called variables. A variable is
characterised by:
• name – it is reffered to as a combination of letters and numbers and it is compulsory
that the first one is a letter: a, Beta, no1, no2
• type: integer, real, string, logic
• value: depending on the type of data, a variable can be assignes one of the above
values;
It is called a variable because its assigned value may vary.
If we want to compare, we can picture a box destined to one purpose only: integer values
in “boxes” for integers, real values in “boxes” for real values and so on.
At the beginning of each algorithm we must state clearly the type of each variable we use.
To solve problems using algorithms, it is necessary to know the type of data assigned to the
variables. Thus, in coding, similar to mathematics, there are key-words for various data
types:
 Simple types
• Integer
• Real
• Boolean(logic)
• Structured data type
• Table
• Set
• String
• File
PRACTICE
Exercise 1
Using the pseudocode language, write the algorithm which reads 2 integer variables
and writes their arithmetical mean.
Indication: The two variables will be assigned integer values while their arithmetical
mean will be a real number, that is will be of real type.

8. Arithmetical mean algorithm
Integer a, b
Real am
Read a, b
am←(a+b)/2
Write “the arithmetical mean of “, a “ and“ , b, “ is=“, am
Stop
Exercise 2
The Ionescus bought a rectangular piece of land with sides of 30m and 20m. The
house they intend to build there is also of a rectangle shape, with sides of 10m and 6m,
while the pool will be a square with the side of 5m. The rest will be lawn. What is the
surface of the lawn?
Indication:
We will code the piece of land dimensions as a and b, the house dimensions as c and d,
and the pool as e. As there are specific values assigned to these dimensions, the variables will be
attributed these respective values. For any other dimensions, these values can be altered, by
assigning them differently. In turn, we will calculate the total surface, the house surface and the
lawn surface. Finally, we will substract from the total surface the sum between the house and
pool surface to get the remaining surface of the lawn.
The algorithm
Integer a,b, hs, ps, ls
a←30
b←20
c←10
d←6
e←5
ts←a•b
s←c•d
hs←e•e
ls←ts-(hs+ls)
Write “the lawn surface =“, ls
Stop