Modular programming

Modular Programming
Chapter-9
Class-10
Presenter By: Bhuwan Bist
Computer Teacher,
Adarah Vidya Niketan Secondary
School
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Overview
• Modular programming is a technique used to divide our
program into many small, manageable and functional
module or block.
• Every modular program has one main module and many sub
module. The sub module of a program is also called as a
procedure.
• Main module is the top level module in which program entry
and exit takes place.
•Sub-Module is a block of statement that is used for specific
task and controlled by main module. Click to adBhuwan_Bista

Structure of Modular Programming
Main
Program-M1
Module-M2
Module-M6 Module-M7
Module-M3 Module-M4 Module-M5
Module-M8
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Advantages of Modular program
It reduces program codes.
 Increases the readability of program.
 Easy to debug program.
 Program maintenance become easier.
Module can be tested independently
Saving the time during project development.
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Types of Procedure in Qbasic Program
In Qbasic, a programmer can name a block of code can
be executed by simple calling out that name. These
name block of code are called procedures.
The two types of procedures are:
1. SUB Procedure
2. FUNCTION Procedure
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SUB Procedure
 A SUB Procedure is a small manageable and functional part
of program that performs specific task and does not return
any value to the calling module.
 The block of statements is placed with a pair of SUB/END
SUB statement and can be called by its name.
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Features of SUB Procedure
SUB procedure cannot be a part of an expression and does not
return any value.
SUB procedure do not have data type.
Argument can be passed to the subprogram by reference and
by value method.
SUB procedure name can't be used as a variable .
SUB procedure is called by CALL statement.
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Declaring SUB Procedure
 The DECLARE statement is used to declare a SUB procedure.
The syntax for the DECLARE statement is as follows:
DECLARE SUB name(parameter list)
Example:
DECLARE SUB volume(L,B,H)
SUB procedure volume with three parameters L,B and H
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Defining a SUB Procedure
oThe SUB....END SUB statement is a procedure
statement that marks the beginning and ending of a
subprogram. The syntax is:
SUB Procedure name [parameter, list]
[Statement]
END SUB
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Call a SUB Procedure
• The CALL statement is used to transfer control to another procedure,
a BASIC SUB program.
• The syntax is
CALL name(argument list)
Example:
CALL circumference(r)
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Example
• Write a program to create a sub-procedure to input the value of length,
breadth and height of a cuboid. The program should calculate the diagonal,
volume and of a cuboid.

FUNCTION Procedure
 A function is a small manageable and functional part of a
program that performs specific task and returns a value to the
main program or calling module.
 It is written with FUNCTON.....END FUNCTON Statements.
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Features of FUNCTION Procedure
⮚ FUNCTON procedure are used in expressions and can directly
returns a single value.
⮚ FUNCTION procedure have a data type which is the return
value of the function.
⮚ The parameters can be passed by reference or by value.
⮚ FUNCTION procedure can be recursive.
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Example
• Write a program to declare a user defined function using FUNCTION.....END
FUNCTION to print the area of a triangle by using expression method.
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The difference between Function procedure and SUB
procedure
SUB Procedure FUNCTION Procedure
The block of statement Is placed with a pair of
a SUB/END SUB statement and be called by
name.
The block of statement is placed with a pair of
FUNCTION/END FUNCTION statements and be
invoked from the reference of the function
name.
It dies nit return any value . It directly returns a single value
It does not have a data type It has a data type which is the return value of
the function.
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What are parameters?
Parameters are variables that receives data (argument values)
and the procedure (SUB/FUNCTION procedure)
Arguments: The constant and variable enclosed in the
parentheses of procedure call statement and that are supplied
to a procedure and known as arguments.
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Modular programming

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