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A general explanation of how functions are used to modularize a program.

Prerequisite material

Critical to this module is the review of several Connexions modules:

  1. m_18861 – Titled: Modularization and C++ Program Layout
  2. m_19136 – Titled: Pseudocode Examples for Functions
  3. m_18682 – Titled: Hierarchy or Structure Chart

You should review these materials before proceeding. If you are viewing this module on-line, links to these items are in the "Links" box to your right.

Concept of modularization

The concept is everywhere present in the real world about us. Simply put it is to take a large complicated problem and to divide it into smaller manageable pieces . The hierarchy chart of any large organization (government unit, company, university, hospital, etc.) will show levels of people with job titles that indicate a different area of responsibility. Each person is a small piece of the overall workings of the organization. Each person can concentrate on their unique talent or task to make sure it works properly. Collectively they accomplish the goals of the organization.  

Additionally, the concept has been around for a long time. A village of 300 years ago had farmers, tailors, butchers, blacksmiths, etc. Manufacturing is a prime example of not just work being modularized but the product itself is viewed in terms of modules or systems (Example of a automobile: engine, steering, brakes, etc.).

The world of computers, both hardware (equipment) and software (computer programs), also uses this modular concept. Thus, the concept migrates to a single computer program; allowing us to modularize the program into manageable tasks called functions.

Program control functions

Program Control functions normally do not communicate information to each other but use a common area for variable storage. The rules for how data is communicated in and out of a function vary greatly by programming language, but the concept is the same. The data items passed (or communicated) are called parameters. Thus the wording: parameter passing . However, with program control functions we use the data communication option of no communication in – with no communication out . Our data variables and constants are placed in a common area available to all functions (called global scope).

The identifier names for program control functions usually imply a task to be accomplished, such as get-data, process-data or show-results. As you learn to write more complicated programs the number of lines of code will increase. Prudence dictates that it would be beneficial to divide the program into functions that perform unique tasks. The larger the program the more need for modularization or creating of program control functions.

Depending on the programming language, there is a formal way to:

  1. define a function (it’s definition or the code it will execute))
  2. call a function
  3. declare a function (a prototype is a declaration to a complier)

One of the easier ways to understand program control function is to view an example. Even if you don’t know the C++ programming language, you can study the materials to help understand the modularization process.

Demonstration program in c++

Creating a folder or sub-folder for source code files

Depending on your compiler/IDE, you should decide where to download and store source code files for processing. Prudence dictates that you create these folders as needed prior to downloading source code files. A suggested sub-folder for the Bloodshed Dev-C++ 5 compiler/IDE might be named:

  • Demo_Programs

If you have not done so, please create the folder(s) and/or sub-folder(s) as appropriate.

Download the demo program

Download and store the following file(s) to your storage device in the appropriate folder(s). You may need to right click on some of the links and select "Save Target As" in order to download some of the files. Following the methods of your compiler/IDE, compile and run the program(s). Study the source code file(s) in conjunction with other learning materials.

Download from Connexions: Demo_Program_Control_Functions_before_Compiler_Test.cpp

Download from Connexions: Demo_Program_Control_Functions_Pseudocode.txt

Download from Connexions: Demo_Program_Control_Functions_Hierarchy_Chart.jpg

Download from Connexions: Demo_Program_Control_Functions.cpp

Study the materials collectively to understand modularization

The four items represent a progression from no modularization to modularization:

  1. Program code before it is modularized
  2. Modularized pseudocode and a hierarchy chart for the program
  3. Program code that has been modularized

The simplicity of the program should not be considered during this review. It is obvious that the program does not need modularization. The example is to show or demonstrate how to modularize a program for program control.

Definitions

common area
An area of the program where variables and constants are defined so that they are available to all functions.

Questions & Answers

What is scarcity.
Npoanlarb Reply
when there is adequate resources
Fiona
why our wants are limited
Npoanlarb Reply
nooo want is unlimited but resources are limited
Ruchi
and do to that there occurs scarcity and we have to make choice in order to have what we need if need be I will explain more
Madara
our wants are not limited but rather the resources
Moses
as we know that there are two principle of microeconomics scarcity of resources and they have alternative uses...
Ruchi
yes .....
Mathias
because our resources are limited./we have a limited resources.
Ijeoma
what is demand
Thank Reply
demand is something wt we called in economic theory of demand it simply means if price of product is increase then demand of product will decrease
Ruchi
inverse relationship between demand and price
Ruchi
in microeconomic
Ruchi
demand is what and how much you want and what's your need...
Shikhar
how can one be so with economics even while you have less knowledge in mathematics.
OKORO Reply
why is it that some products increases everyday by day
Chiamaka Reply
because demand is increase
Ruchi
because demand is increase
Patience
but how demand increases?
Aziz
Because of the Marketing and purchasing power of people.
AmarbirSingh
but how could we know that people's demands have increased everyday by day and how could we know that this is time to produced the products in the market. Is any connection among them
yaqoob
for normal good people demand remain the same if price of product will increase or not
Ruchi
see that some product which increases day by day is comes under normal good which is used by consumer
Ruchi
Seems hot discussing going here
Shamamet
If there are less products demand starts to increase for those products
Shamamet
Economics is really interesting to learn ....
Shamamet
see there is Inferior goods ands normal goods inferior good demand is rarely increase whereas as we talk about normal good demand will absolutely Increase whether price is increase or not
Ruchi
and demand for normal goods increase cause people's income as a while increases time to time
Abhisek
and it might also be that the cost of raw materials are high.
ATTAH
may be
Ruchi
obviously because demand is increasing.....and price is getting low.....
Shikhar
hmmm there is inverse relationship between demand and price
Ruchi
This is because the supply of those products in relation to raw materials are decreasing and they are also necessities. This crate shortage in the market, so sellers will rise the prices of those products.
Abdul
Importance of economics
Odunayomi Reply
the nature and significance of economics studies
Deborah
What is demand
Shuaib Reply
deman is amount of goods and services a consumer is willing and able to buy or purchase at a given price.
Sainabou
the willingness and ability of a body to purchase goods nd servicesbis called demand ,so if she/has ability but doesn't have willingness it's not a demand same if she or he has willingness but doesn't has ability it's not a demand too
Gul
Demand refers to as quantities of a goods and services in which consumers are willing and able to purchase at a given period of time and demand can also be defined as the desire or willingness and backed by the ability to pay.
Fadiga
Yeah
Mathias
What is Choice
Kofi
Choice refers to the ability of a consumer or producer to decide which good, service or resource to purchase or provide from a range of possible options. Being free to chose is regarded as a fundamental indicator of economic well being and development.
Shonal
choice is a act of selecting or choosing from the numerous or plenty wants.
Fadiga
demand is want and it is also what you need and able to afford a particular period of time... because demand changes with time.
Ijeoma
Demand refers to the ability of the consumer to pay for a particular product at a given price
Abdul
how does consumer make profit
Clifford Reply
by buying goods in bulk.
Ijeoma
Compare and contract the function of commercial bank and the central bank of Nigeria
Akwi Reply
what do think is the difference between overhead costs and prime cost
Abdoulkarim
what is economics
Mohamed Reply
economics is a social science that study's how resources can be used to produce goods and services for society
Nathan
Economic is a science which studies human behavior as a relationship between ends and scares means which have alternatives uses or purposes.
Fadiga
what is economics
Mohamed Reply
what is the basic economic problem
John Reply
rules
Buayadarat_Gaming
unlimited wants vs limited resources
Nathan
what economics is all about?
Nomuhle Reply
what is a new paradigm shift
Austen Reply
Paradigm shift it is the reconcilliation of fedural goods in production
Shyline
fedural? what is that?
Aziz
factors that affecting economic system
Bemen Reply
crux
Shyline
what is meant by broadening the tax base?
Fiona Reply
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Source:  OpenStax, Programming fundamentals - a modular structured approach using c++. OpenStax CNX. Jan 10, 2013 Download for free at http://cnx.org/content/col10621/1.22
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