This presentation has created for Ordinary Level ICT students.

1. Write programs to solve problems
Pascal Programming
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By Anutthara Senanayake
Lecturer
Sri Lanka International Buddhist Academy

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Session 01
A problem
Input, Output and Process
Alternative solutions
Algorithm
Control Structures in Algorithms
To display Algorithms : Flowcharts & Pseudocodes
Pascal Programming
Why Pascal is more popular ?
Turbo Pascal
Identifiers
Reserved Words
Data Types
Variables
Constants
Program Structure
Control Structures
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A Problem
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Problem 01
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Input , Output & Process
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Algorithms
Definition
An algorithm is a
procedure or
formula for solving
a problem.
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Control Structures in Algorithms
Sequence
Selection
Iteration
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To display Algorithms : Flowcharts &
Pseudocodes
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Pascal Programming
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Pascal is a general-purpose, high-level
language that was originally developed by
Niklaus Wirth in the early 1970s.
It was developed for teaching programming
as a systematic discipline and to develop
reliable and efficient programs.

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Why Pascal is more popular ?
Easy to learn.
Structured language.
It produces transparent, efficient and reliable programs.
It can be compiled on a variety of computer platforms.
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Turbo Pascal
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Additional Notes
How to run turbo Pascal in Dos Box - Type following commands
Mount c C:TP
C:
Cd BIN
turbo.exe
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Identifiers
Identifiers are names that allow you to reference stored
values, such as variables and constants.
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Exercise 01
Select the valid identifiers from the given list.
1. Myname
2. @me2
3. me2
4. saman
5. my-add
6. my_add
7. $sea_u 14

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Reserved Words
program, input, output, var, real, begin, readline, writeline , end
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Data Types
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Variables
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var myname : string

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Constants
A const is a keyword
applied to a data type
that indicates that the
data is constant (does
not vary).
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Const pi=22/7;

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Operators
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Arithmetic Operators
Relational Operators
Logical Operators

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Program Structure
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Program Name
Library
Main program starting
point
Main program ending
point
Output

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Exercise 02
Write a Pascal program to calculate the sum of two integer
numbers.
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Control Structures - IF…THEN…ENDIF
Exercise 03
Write a Pascal program to print the entered, number if it is
only a positive number.
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Exercise 04
Write a Pascal program to print “Pass” if the mark is greater
than 50.
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Control Structures - IF….THEN….ELSE…..ENDIF
Exercise 05
Write a Pascal program to find the maximum number out of
two given numbers.
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Control Structures -Nested IF
Exercise 07
Write a Pascal program to print the correct grade for the
given mark. (mark >= 75 =>A, mark >=65=> B, mark >=50 =>C,
mark =>35=>S, else F)
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Exercise 08
Write a Pascal program to display the day of the week when
the day number is provided.
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Control Structures - CASE statements
Exercise 09
Write a Pascal program to print the grade according to the
criteria for the given mark.
0-34 => F , 35 – 49 =>S , 50 – 64 =>C, 65 – 74 => B, 75 – 100
=>A
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Control Structures - FOR - DO
Exercise 10
Write a Pascal program to print numbers starting from 10 to
1.
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Exercise 11
Write a Pascal program to calculate the sum and the average
of given 10 numbers.
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Control Structures -WHILE DO
Exercise 12
Develop a computer based solution to receive a set of
positive numbers or 0 from user and display the total value.
Data input will stop when a negative value is entered.
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Control Structures - REPEAT UNTIL
Exercise 13
Write a Pascal program to print the word “Pascal” 5 times.
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Control Structures - Nested Control Structures
Exercise 14
Write a Pascal program to make a number series according
to the ascending or descending order
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Exercise 15
Write a Pascal program to input numbers and calculate the
count of odd numbers and the count of even numbers.
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Lets do some more on Pascal
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Session 02
Arrays
Declaring Arrays
Assigning Values
Accessing Values
Sub Programs
Functions
Defining a Function
Function Declarations
Calling a Functions
Procedures
Defining a Procedure
Procedure Declarations
Calling a Procedure
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Arrays
An array is a highly useful
data structure that stores
variable data having
the same data type
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An array is said to be a static data structure because, once declared, its original
size that is specified by the programmer will remain the same throughout the
whole program and cannot be changed.

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Declaring Arrays
Syntax
Var
<arrayName> : Array[n..m] of <Data Type>;
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Assigning Values
Syntax
<arrayName>[index] := <relevant data>
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Accessing Values
By using a for loop we can easily access the array
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Exercise 01
Write a Pascal program to find the sum of a given integer array.
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Sub Programs
• A subprogram is a program unit/module that performs a particular task.
• These subprograms are combined to form larger programs.
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Pascal provides two kinds of subprograms:
Functions: these subprograms return a single value.
Procedures: these subprograms do not return a value
directly.
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Functions
A function is a group of statements that together perform a task.
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Function Declarations
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Calling a Functions

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Procedures
Procedures are subprograms that, instead of returning a single value,
allow to obtain a group of results.
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Procedure Declarations
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Calling a Procedure

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53. Thank you !
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