Flowchart

FLOWCHART

1. INTRODUCTION

A flowchart is a diagrammatic representation, that illustrates the sequence of operations to be performed to arrive at the solution.

A flowchart uses different shaped symbols to denote the different appropriate instructions and these instructions can be written within the boxes using clear statements. Then these boxes are connected by lines having arrow marks to indicate the flow of operations, that is the exact sequence in which the instructions are to be executed.

2. NEED FOR FLOWCHARTS

A flowchart uses different shaped boxes to specify the several types of instructions. The program logic is made very easy through the flowchart that have standardised meaning.

Thus, every programmer uses the same basic shapes, so others can easily read and interpret the logic of the program. When the programmer looks at a flowchart, it can be easily identified.

3. AIMS OF FLOWCHARTS

a) Program preparation can be simplified using the flowcharts.

b) Flowcharts are easier to understand at a glance, than the narrative description of algorithm.

c) Flowcharts are easy to analyse and compare various methods.

d) Flowcharts assist in reviewing and debugging of a program.

e) Flowcharts provide effective programming documentation.

f) Using flowcharts, the method of solution adopted in a problem can be quickly understood, instead of going through the tedious process of reading all the program statements.

4. FLOWCHART SYMBOLS

For easy visual recognition, a standard conventions are used for drawing flowcharts. The flowchart symbols as given below are as per connection followed by International Standard Organization (ISO).

i. Flowlines: These are the left to right or top to bottom lines connecting symbols. These lines show the flow of control through the program.

ii. Terminal symbol: The oval shaped symbol always begins and ends the flowchart. It is the first symbol and the last symbol of the program logic of flowchart. The start symbol will have only one flow line but not entering flow line and a stop will have an entering flow line but no exit.

iii. Input/Output symbol: The parallelogram is used for both Input (Read) and Output (Write), such that this symbol is used to denote any function of an I/O device in the program.

iv. Process symbol: The rectangle symbol is used primarily for calculation and initialization of memory locations. All the arithmetic operations, data movements, initialization operations.

v. Decision symbol: The diamond shaped symbol is used in a flowchart to indicate a point at which a decision has to be made and a branch to one of two or more alternative point is possible. There will be always two exits from a decision symbol, one is labelled YES or TRUE and other labelled NO or FALSE. This is the only symbol that can have two exits.

vi. Connectors: A connector symbol is represented by a circle and a letter or digit placed in the veros bons circle to specify the link. Whenever a complex flowchart is to be drawn with a number of direction of flow lines is confusing or it is long as over more than one page, in such a situation, the connector symbols are used to connect the flowchart.

5. RULES FOR DRAWING A FLOWCHART

In order to produce an efficient flowchart, the designer must follow the rules given below.

• The standard symbols should only be used.

• The arrowheads in the flowchart represents the direction of flow of control in the problem.

• The usual direction of the flow of procedure is from top to bottom or left to right.

• Only one flow line should come to a process symbol and only one flow line should be out from a process symbol.

• Only one flow line should enter a decision symbol, but two or three flow lines, one for each possible answer, should leave the decision symbol.

• Only one flow line is used in conjunction with terminal symbol.

• Write within standard symbols briefly. As necessary, use the annotation symbol to describe data or computational steps more clearly.

• The flow lines should not cross each other.

• Be consistent in using names and variables in the flowchart.

• Keep the flowchart as simple as possible.

• Words in the flowchart symbols should be common statements and easy to understand.

• Chart the main line of logic, then incorporate all the details of logic.

• If a new page is needed for flowcharting, then use connectors for better representation.

• Don't chart every detail or the flowchart will only be graphically represented.

Tips for Preparing Flowcharts

1. Know your symbols.

2. Create charts that flow from the top to the bottom of the page.

3. Navigational lines should not intersect.

4. Try to fit flowcharts on as few pages as possible.

5. Use the simplest method when flowcharting.

6. BASIC DESIGN STRUCTURES IN FLOWCHART

By using the basic flowchart symbols, we can design any program. Then we will be combining them to design solutions to more complicated problems. In fact, the ways in which we combine them have a lot to do with the clarity and acceptability of our design. There are three generally accepted design structures, such as sequence, selection and loop.

1. Sequence structure

It is the simplest, because it is nothing more than a series of statements performed one after another. It is a sequence because the flow sw always continues in the same direction every time the structure is executed.

A sequence may include a number of instructions, but each would be done in turn in the same order.

2. Selection structure

Selection structure uses a decision to ask some question. This structure includes the decision and the operations to be performed in response to the decision. There will be two exits from the decision, but both of these branches are still at part of the selection structure, then both branches must re‒join a single flow line to exit the structure. Using this selection structure, different steps may be executed depending on the result of the decision test.

If the selection only has an operation the true side, then it is called a one‒sided selection, with this one‒sided structure the "null" side still must have its exit from the decision box.

3. Loop structure

The loop structure is used to execute a sequence of steps in a number of times or until a particular condition is met. This structure will have a decision, one or more additional symbols indicating the steps to be done within the loop and a flow line that sends control to back to the beginning of the loop. Commonly there are two loops available, one is top tested loop and another is bottom tested loop.

a) Top tested loop

The top tested loops are leading decision loops, means that the decision is evaluated the first statements of the loop. If it is true, the control follows the flow lines that go into the loop. If it is false, control follows the flow line to the first statement after the loop.

b) Bottom tested loop

This loop is a trailing decision loop, which means that the decision is always at the last statement of the loop. The body of the loop will be executed once before control even gets to the loop test. In this loop, if the condition is false, control follows the flow line back to the loop. If the test is true, control follows the branch from the decision box that exits the loop structure.

7. ADVANTAGES OF FLOWCHARTS

The use of flowcharts has several advantages which are given below:

i) To understand logic clearly: Before coding the program, the programmer must be known about the logic of the program. To make 6b or logic easier the programmer has to follow the task that provides pictorial to representation. If programmer has a clear idea about the logic, then only they will produce good programming.

ii) Better communication: The flowcharts are better for communication, because "a picture is worth thousand words." It is very easy for the programmer to explain the logic of the program through the flowchart.

iii) Effective Analysis: The flowcharts are very well suited to analyse the problem and can be broken down into parts for study and further analysis of the system.

iv) Effective synthesis: A team of designers or programmers are associated with the design of complex system. Each designer or programmer is responsible for designing a part of the entire system. So initially each designer or programmer draws a flowchart for their part, then all the flowcharts from all the designers or programmers can be placed together to visualize the overall system.

v) Effective coding: After designing the flowchart, it is very easy to write programs, because flowchart is the road map for the programmers.

vi) Proper program documentation: The documentation involves collecting, organizing and storing a complete record of program i.e., the flowcharts obviously provide the documentation support.

vii) Systematic Debugging: After taking full care in program design, there may be chances for some errors. Such errors can easily be found out in the flowcharts, and these can be eliminated easily.

viii) Systematic Testing: It is the process of executing the designed and developed program with sample data. A flowchart is helpful in designing the test data for systematic testing of programs.

ix) Efficient Program Maintenance: The maintenance of operating program becomes easy with the help of flowchart. It helps the programmer to put efforts more efficiently on that part.

8. PROGRAMMING LANGUAGES

Programming languages are languages used to communicate with computers to create software, websites, applications, and other technology. They allow people to write instructions for computers to follow and create the technology we use every day. Programming languages are essential in technology because they enable us to automate tasks, make calculations, and process large amounts of data quickly and efficiently.

Tabs There are several programming languages that use paradigms, but to do this, they need to follow a strategy or methodology. Below is an overview of programming languages and their paradigm methodology.han the

• Imperative: Programming with an explicit sequence of commands.

• Declarative: Programming by specifying the result a user wants, instead of how to get it.

• Structured: Programming with clean control structures.

• Procedural: Imperative programming with procedure calls.

• Functional: Programming with function calls that avoid any global state.

• Object‒Oriented: Programming by defining objects that send messages to each other.

• Logic: Programming by specifying a set of facts and rules.

• Constraint: Programming by specifying a set of constraints.

• Reflective: Programming by manipulating the program elements.