Flowchart in C Language

7/30/2019 Flowchart in C Language

1/27

FLOW CHARTING

Nihar Ranjan Roy


2/27

What is a Flowchart?

A flowchart is a diagram that depictsthe flow of a program.

The figure shown here is a flowchartfor the addition of two numbers.

START

Display messagePlease entertwo numbers

Read two

Numbers

Calculate theSum

Display Sum

END

2Nihar Ranjan Roy


3/27

Basic Flowchart Symbols

Notice there are three types of symbols in this flowchart:

rounded rectangles parallelograms

a rectangle

Each symbol represents a different type of operation.

SymbolSymbol NameName MeaningMeaningovals or roundedrectangles (terminals)

Start or end of a process

Arrows Flow of control

parallelograms Input/output

Rectangle Processing (indicates a process such as amathematical computation or variableassignment)

3Nihar Ranjan Roy


4/27

Flow of control in flow chart

START

Display messagePlease enter two

numbers

Read twoNumbers

Please enter two

numbers

Output operation

Calculate the

Sum

Display Sum

END

4Nihar Ranjan Roy


5/27


START

Display messagePlease enter twonumbers

Read twoNumbers

Please enter two

numbers

12 13

Read operation

Calculate the

Sum

Display Sum

END

Accept the value and store them into variables

Fno

Sno

5Nihar Ranjan Roy


6/27


START


Read twoNumbers

Please enter two

numbers

12 13

Calculate the

Sum

Display Sum

END

Processing /calculation

Processing/calculate

Sum=Fno+Sno

6Nihar Ranjan Roy


7/27


START


Read twoNumbers

Please enter two

numbers

12 13

25

Calculate the

Sum

Display Sum

END

Output

7Nihar Ranjan Roy


8/27

Four Flowchart Structures

SequenceDecision

RepetitionCase

8Nihar Ranjan Roy


9/27

Sequence Structure

A series of actions are performed in sequence

The addition of two numbers was a sequential activity

9Nihar Ranjan Roy


10/27

Decision Structure

One of two possible actions is taken, depending on a condition.

A new symbol, the diamond, indicates a yes/no question.

If the answer to the question is yes, the flow follows one path.

If the answer is no, the flow follows another path

YESNO

10Nihar Ranjan Roy


11/27

PROBLEM

Accept two numbers and find the square of

Nihar Ranjan Roy 11


12/27

Decision Structure

In the flowchart segment below, the question is x < y? is asked. If theanswer is no, then process A is performed. If the answer is yes, then

process B is performed.

YESNO

Square=y*y

x < y?

Square=x*x

12Nihar Ranjan Roy

If (x


13/27

Repetition Structure

A repetition structure represents part of the

program that repeats. This type of structure iscommonly known as a loop.

13Nihar Ranjan Roy


14/27


Notice the use of the diamond symbol.

A loop tests a condition, and if the condition exists, it performs anaction. Then it tests the condition again. If the condition still exists,the action is repeated.

This continues until the condition no longer exists.

Condition?Condition?

14Nihar Ranjan Roy

YES

No


15/27


In the flowchart segment, the question is x < y? is asked. If theanswer is yes, then Process A is performed.

The question is x < y? is asked again. Process A is repeated as long asx is less than y.

When x is no longer less than y, the repetition stops and the structureis exited.

x < y?Do some

Processing

YES

15Nihar Ranjan Roy


16/27

PROBLEM

Print your name 5 times

Nihar Ranjan Roy 16


17/27


The flowchart segment below shows a repetition structureexpressed in C as a while loop.

Flowchart

i=0

i=0;

while (i < 5)

{

puts(nihar Ranjan roy);

i=i+1;

}

i< 5?

Printname

i=i+1

YES

17Nihar Ranjan Roy


18/27

Caution: Controlling a Repetition Structure

The action performed by a repetition structure must eventually causethe loop to terminate. Otherwise, an infinite loop is created.

In this flowchart if i is never changed. Once the loop starts, it willnever end.

QUESTION: How can this flowchart be modified so it is no longeran infinite loop?

18Nihar Ranjan Roy

i< 5?

Printname

YES

i=0;

while (i < 5)

{

puts(nihar Ranjan roy);

}

C

Code


19/27

Controlling a Repetition Structure

ANSWER: By adding an action within the repetition that changes thevalue of i.

YES

Print namei < 5? i=i+1

19Nihar Ranjan Roy


20/27

Case Structure

One of several possible actions is taken, depending on the contents ofa variable.

20Nihar Ranjan Roy


21/27

Case Structure

The structure below indicates actions to perform depending on the valuein years_employed.

CASEyears_employed

1 2 3 Other

bonus = 100 bonus = 200 bonus = 400 bonus = 800

21Nihar Ranjan Roy


22/27

Case Structure

If years_employed = 2,

bonus is set to 200If years_employed = 3,

bonus is set to 400

CASEyears_employed

1 2 3 Other

bonus = 100 bonus = 200 bonus = 400 bonus = 800

If years_employed = 1,bonus is set to 100

If years_employed isany other value, bonus

is set to 800

22Nihar Ranjan Roy


23/27

Connectors

Sometimes a flowchart will not fit on one page.

A connector (represented by a small circle) allows you to connect two

flowchart segments.

A

23Nihar Ranjan Roy


24/27

Connectors

ASTART

The A connector

indicates that the second

flowchart segment begins

A

END

where the first segmentends.

24Nihar Ranjan Roy


25/27

Modules

A program module (such as a function in C) is represented by a specialsymbol.

25Nihar Ranjan Roy


26/27

Modules

The position of the module

symbol indicates the point the

module is executed.

START

Read Input.

A separate flowchart can beconstructed for the module.

END

Call calc_pay

function.

Display results.

26Nihar Ranjan Roy


27/27

Problem

Design an algorithm and flow chart for

converting an integer number to its binaryequivalent.

Nihar Ranjan Roy 27

Documents

Flowchart in C Language