Flowcharts for Programming - Lecture 1 | Prof. Kamal Ghanshala | Graphic Era University

Summary

This video script offers a comprehensive introduction to flowcharts, emphasizing their utility in programming for maintaining the sequence of instructions. It explains the significance of sequencing in programs and how flowcharts assist in this process. The script outlines the basic symbols used in flowcharts, such as start/stop, input/output, assignment, decision, and connectors. It illustrates these concepts with examples, including generating bills for mango sales with varying levels of input requirements, and calculating the average of three numbers. The script also highlights the importance of proper syntax in flowchart assignments to ensure accurate program translation.

Takeaways

• 📝 A flowchart is a diagrammatic representation of a process, useful for maintaining the proper sequence of instructions in programming.
• 🔢 A program is a set of instructions in a specific sequence, and flowcharts help in visualizing this sequence before writing the actual program.
• 🏁 Flowcharts start with a 'start' symbol, which is a box rounded at both ends, and end with a similar 'stop' symbol.
• 📥 The 'input' or 'read' statement in a flowchart represents the values supplied by the user, which are stored in variables like n1, n2, and n3.
• 📤 The 'print' or 'output' symbol, shown as a parallelogram, is used to display results from the program.
• 🔄 The 'assignment box', a rectangular symbol, is used for calculations, such as assigning the result of a formula to a variable.
• ❓ The 'decision box', in a diamond shape, represents a yes/no decision in the flowchart, such as checking if one value is greater than another.
• 🔗 Connectors are used when continuing a flowchart in a different part of the diagram, represented by a circle with a label inside.
• 🍋 Examples in the video include generating a bill for mango purchases, where known values or user inputs are used to calculate the total cost.
• 🔢 Another example includes calculating the average of three numbers inputted by the user, with emphasis on correct syntax when writing equations in programming.

Q & A

What is a flowchart?

A flowchart is a diagrammatic representation of a process, used in programming to maintain the proper sequence of instructions.

Why is sequencing important in a program?

Sequencing is important in a program because it ensures that the set of instructions are executed in the correct order.

What is the first step in drawing a flowchart?

The first step in drawing a flowchart is to write 'start' and then draw a rounded box from both ends to represent the beginning of the process.

How is input represented in a flowchart?

Input in a flowchart is represented by writing 'input' or 'read' followed by a list of arguments, such as 'n1, n2, n3', which signifies that the user will supply three values.

What symbol is used to represent output in a flowchart?

Output in a flowchart is represented by a parallelogram, with 'print' followed by the list of arguments whose values are to be displayed.

What is an assignment box in a flowchart?

An assignment box in a flowchart is a rectangular box used to represent calculations or assignments, such as 'result is equal to a into b plus c'.

How are decisions represented in a flowchart?

Decisions in a flowchart are represented by a diamond-shaped box, which indicates a yes/no type of decision, such as 'a greater than b'.

What is the purpose of a connector in a flowchart?

A connector in a flowchart is a circle with a label (like 'x') used to indicate where the flowchart resumes after a jump or loop.

How does a flowchart help in generating a bill for Bogilal's mangoes?

A flowchart helps in generating a bill for Bogilal's mangoes by diagrammatically outlining the steps to calculate the total cost based on the rate per mango and the number of mangoes bought.

What is the significance of a 'stop' symbol in a flowchart?

The 'stop' symbol in a flowchart signifies the end of the process or program, indicating where the flowchart concludes.

How can a flowchart be used to find the average of three numbers?

A flowchart can be used to find the average of three numbers by diagramming the steps to input the numbers, calculate their sum, divide by three, and then print the average.

Outlines

00:00

📊 Introduction to Flowcharts

This paragraph introduces the concept of flowcharts in programming. A flowchart is defined as a diagrammatic representation of a process, crucial for maintaining the sequence of instructions in a program. The paragraph explains that a program is a set of instructions in a proper sequence, and flowcharts are used to visualize and maintain this sequence before writing the actual code. The paragraph also describes the basic elements of a flowchart, such as the start and stop symbols, input and output symbols, assignment boxes, decision boxes, and connectors. The speaker uses examples to illustrate how these elements are used in flowcharts to represent different programming constructs.

05:02

🛒 Flowchart for Generating a Bill

This paragraph delves into the application of flowcharts by demonstrating how to create a flowchart for generating a bill for mangoes sold by Bogilal. The speaker presents three scenarios with increasing complexity: a fixed sale of five mangoes at a fixed rate, a sale where the number of mangoes is variable but the rate is fixed, and a scenario where both the rate and the number of mangoes are variable and need to be input by the user. Each scenario is explained with a corresponding flowchart, highlighting the use of input, calculation, and output steps. The paragraph emphasizes the flexibility of flowcharts in adapting to different program requirements.

10:03

🔢 Flowchart for Calculating Average

The paragraph focuses on creating a flowchart to calculate the average of three numbers. It discusses the need for user input to supply the three numbers and then describes the steps involved in calculating the average. The speaker explains the use of input boxes to gather the numbers, an assignment box to calculate the sum, and another assignment box to compute the average by dividing the sum by three. The paragraph also includes a discussion on the correct way to format calculations in flowcharts to ensure they are represented accurately and can be translated into valid computer statements.

15:05

🔄 Flowchart Simplification and Common Mistakes

In this paragraph, the speaker discusses the possibility of simplifying the flowchart for calculating the average of three numbers by combining steps into a single line. They also address common mistakes made by students when writing calculations in flowcharts, such as not properly enclosing the entire expression in parentheses, which can lead to incorrect calculations. The speaker emphasizes the importance of continuity and proper formatting in flowcharts to ensure they accurately represent the intended program logic.

Keywords

💡Flowchart

A flowchart is a diagrammatic representation of a process or program. In the context of the video, it is used to visually map out the sequence of steps a program follows, ensuring logical flow and proper structure. For example, the instructor draws flowcharts to illustrate how different values like input or calculations are processed in a program.

💡Start/Stop

These are special symbols used in flowcharts to mark the beginning and the end of the process. The 'start' box signals the commencement of the program, and the 'stop' box marks the end. Both symbols are represented as rounded rectangles, as mentioned when the instructor explains how every flowchart begins with 'start' and concludes with 'stop'.

💡Input

Input refers to values that the user provides to a program during execution. In the video, the instructor demonstrates how the input is represented in flowcharts using the example of a program where the user provides values like the number of mangoes or the rate. Inputs are crucial for the flexibility of programs, allowing dynamic behavior based on user data.

💡Output

Output represents the result displayed by the program after processing the inputs. In the flowchart, output is depicted by the 'print' statement inside a parallelogram. For instance, in the flowchart to calculate the total bill for mangoes, the output is the total bill which is displayed to the user.

💡Decision Box

The decision box is used to represent a logical decision in a flowchart, typically asking a 'yes' or 'no' question to direct the flow of the process. In the example from the video, the decision box is used to compare values, such as whether 'A' is greater than 'B'. Based on the result, the flow proceeds in one of two directions.

💡Assignment Box

An assignment box is a rectangle used to represent a calculation or assignment operation in a flowchart. In the video, the instructor demonstrates this by assigning the result of an expression, like 'result = A * B + C', where a computation takes place and the result is stored in a variable. This is essential for performing operations in a program.

💡Connector

A connector is used to link different parts of a flowchart, especially when space is limited. It is depicted as a circle with a label, allowing the flowchart to resume from the point marked by the connector. In the video, the instructor explains how connectors are useful when continuing the flow of a process from one part of the chart to another.

💡Input/Output Box (Parallelogram)

The input/output box, often shown as a parallelogram, is used to represent operations where the program takes in data (input) or displays information (output). For example, the 'input' box is used when the user provides the number of mangoes, and the 'output' box is used to print the calculated bill.

💡Program

A program is defined as a set of instructions executed in a specific sequence. The flowchart helps visualize and maintain this sequence, ensuring the program runs logically. In the video, the instructor provides examples of small programs, such as calculating the total cost of mangoes, that follow a precise sequence from input to output.

💡Calculation

Calculation refers to the mathematical operations performed within the flowchart, such as summing values or computing totals. For instance, the video illustrates a flowchart where the bill is calculated by multiplying the number of mangoes by the rate, demonstrating how programs use basic arithmetic to solve problems.

Highlights

Flowcharts help in maintaining the proper sequence of instructions in a program.

A program is a set of instructions in a proper sequence, and flowcharts help in planning the sequence.

Flowcharts start with a 'Start' box and end with a 'Stop' box, both rounded at the ends.

User input in a flowchart is indicated with an input or read statement, followed by a list of arguments.

The 'Print' command in a flowchart is used to display output values to the user.

Calculations are represented by assignment boxes in rectangular shapes.

Logical decisions are made using decision boxes that allow 'Yes' or 'No' type decisions.

Connectors in flowcharts, marked with circles, help resume the process from a specific point.

Problem example: Bogilal sells mangoes at a fixed price of 10 per mango. The flowchart directly calculates and prints the bill for a known number of mangoes.

In a more flexible flowchart, the user inputs the number of mangoes, and the bill is calculated based on user input.

For variable rates, the user inputs both the number of mangoes and the rate per mango, and the bill is calculated accordingly.

Problem: Find the average of three numbers. The flowchart includes user input for three values, calculation of the sum, and division by 3 to get the average.

The flowchart can be simplified by combining the calculation and input steps into a single line.

Important note: Incorrect formula formatting, such as breaking the average calculation into multiple lines, results in invalid computer code.

The correct approach is to write the entire expression, such as the average calculation, in one continuous line.

Transcripts

today we are discussing flowcharts

so what is a flowchart first of all let

us define a flowchart a flowchart is a

diagrammatic representation of a process

okay

in programming it helps us in

maintaining the proper

sequence of instructions so first of all

let us see what is a program

a program is a set of instructions

in a proper sequence ok so sequencing is

very important in program and for

maintaining the sequence

before writing the program what we do we

draw a flowchart flowchart helps us in

maintaining

the sequence of a program ok

whenever we start drawing a flowchart we

write start

and then we close start

ok to this type of box which is rounded

from both the

ends see whenever we

complete our flowchart we write stop

again we draw same type of box which is

rounded from

ok here and here

see whenever user supplies some values

to the program which is called input

inputting the values okay

so what we do we write input or we write

read

and then we write list of arguments

suppose i am writing

n one comma n two comma n3

it means whenever this program will get

executed at that time user will supply

you three values

okay first value will replace n1 second

value will replace

n2 and third value will replace n3 okay

similarly whenever we want to

display something to outside world

whenever the programmer wants to display

something

some result to outside world then what

he will be doing he'll be writing

print

and again list of arguments whose values

you want to

display ok suppose arguments are

a one comma a two comma a three so i

will be writing a one

comma a two comma a three

so whenever this program will get

executed

the values of a one a two and a three

will be printed or will be displayed

ok similarly when we have to do some

calculation

then we draw assignment box ok

which is our rectangular box so this is

this type of rectangular box is called

assignment box

suppose i am writing

result is equal to a

into b plus

c so what will happen first of all

this a into b plus c will be calculated

so this will be calculated and this will

be assigned to

result okay so this is called assignment

box where right hand side gets

calculated and gets assigned to

left hand side okay

now suppose we have to take a decision

suppose

we are moving in this direction and now

we have to take a decision

ok logical decision then will be drawing

a decision box like this

ok suppose this is a logical decision it

means ah yes no type of decision

h a greater than b

ok if it is yes

then i am moving in this direction and

if it is

no then i am moving in

this direction because either a will be

greater than b or it will be smaller

than or equal to

b so this is called a decision box

at times you require some connectors

also

ok suppose

now i do not have space here so now what

will i be doing i will be drawing a

connector here suppose i draw a

connector it is a

circle i draw a connector here and i

write

x here it means

now i will be starting from i will be

resuming from

x so now if i write x

and like this it means whatever i have

left here now i am

resuming from here so this is called a

connector

ok so so far we are discussing only

these many symbols because so far we

wont be drawing loops whenever

we draw loops then will be draw we will

be discussing

some more symbols ok so now let us start

drawing some basic flowcharts see our

first

problem is like this problem number one

bogilal sells mangoes at rupees 10

per mango mohan bought five mangoes from

bogie lal

now we have to draw a flow chart to

generate bill

okay now here we know what is the rate

rate is rupees 10 per mangoes how many

mangoes

one bought five mangoes ok so

we will be drawing flow chart like this

now we need not to input anything

because we already know everything we

know the rate we know the number of

mangoes so

we need not to input anything we will be

drawing a flowchart like this

start

we can directly calculate bill we may

write

well is equal to rate is 10

into number of mangoes is 5

and after that once we know the bill

then will be printing the value of

bill so will be drawing a parallelogram

and will be writing

print bill

ok and after that i am writing

stop

so whenever a programmer will make a

program according to this flowchart

ok that program will not input anything

whenever that program will get executed

it will

be directly generating the value of bill

and which will always be

rupees 50 okay so

normally our flow charts are not as

simple as this one

so let us take one more example

next one now let us discuss

bit more generalized type of problem

problem number two bogilal sells mangoes

at rupees 10 per mango

okay so rate is fixed draw flow chart to

generate

bill now if we have to generate well we

must know how many mangoes a customer

is buying so that is not given it means

that will be

inputted in our program ok that will be

asked from the user whenever this

program will get executed

that value will be supplied by the user

ok so now we have a flexibility earlier

we were selling only five mangoes now

we may change number of mangoes because

the user will decide how many mangoes he

has to

buy so now we'll be drawing our flow

chart like this will write start

now we are now deciding number of

mangoes number of mangoes

will be supplied by the user so we'll be

writing

input input means user will supply

input number of

mangoes okay here we may write n m means

number of

mangoes so input number of mangoes

and m and

after that we are writing once we know

number of mangoes because rate is fixed

so what will be our bill our

bill will be equal to 10

that is the rate and into number of

mangoes

what do we do after this

after this since we have calculated well

so we have to display to the outside

word so will be using a

print statement so

what will have will be enclosing it in a

parallelogram and then we will write

print

i'll write print bill so whenever this

program will get executed ok because we

are drawing flowchart then based on this

flowchart

what will happen programmer will write

program

and whenever this program will get

executed

at that time what will happen ok

whenever

programmer writes a program according to

this flowchart and that program gets

executed so

at the execution time first of all

here the program will ask input number

of mangoes so the user will have to

supply

number of mangoes okay then the program

will calculate

and then the program will display

ok print or display bill ok whatever

bill we have calculated that will be

displayed to

outside work ok that is how this

flowchart will work

now let us take our problem number 3

which is

more generalized ah here bogilal is

selling mangoes

ok because rate may change every day so

rate is not given

draw flow chart to generate bill so here

rate is not given and number of mangoes

because number of mangoes will also

change from customer to customer so that

is also not

given so from where will we get rate and

number of mangoes

so both have to be inputted ok

have to be whenever we have to generate

build so both these values have to be

inputted have to be supplied

by the user okay so

our flowchart will be like this start

now i have to input input

first of all number of mangoes

and rate

okay

we may specify what is nm nm is

number of mangoes

once we know number of mangoes and rate

then we can very well find bill

what will be our bill

bill is equal to number of mangoes

into rate ok basically its rate per

mango

so once we know number of mangoes and

rate of mango

red per mango then we can always

calculate bill is equal to number of

mangoes

into our rate

ok and after that what we do once we

know the

bill then what we can do we can display

parent bill

and after that we stop

ok so now what happens

whenever somebody writes a program

according to this flowchart

this is small r whenever somebody writes

a program according to this flowchart

then and see once a program is returned

so first of all it is compiled it means

it is changed

it is translated to machine language ok

and after that its

loaded and after that you may execute it

so whenever this program will get

executed so

first of all

at this point see

user need to supply two values ok the

program will ask user to supply

two values at this point number of

mangoes

and rate per mango okay based on

these two values the bill will be

calculated

and once bill will is calculated the

value of bill will be

printed here okay so now if some user is

executing this program so he need to

supply two values first is number of

mangoes second is rate

and soon after supplying these two

values will

get a value which will be the value of

bill okay so this is our problem number

one problem number three now we are just

okay for for some time we are shifting

from bogilal

okay we are taking one more very simple

flowchart draw flowchart to find

average of three numbers ok

so now this has to be a generalized

program which should be able to find

average of any three numbers okay

now the question arises who will be

supplying those numbers

the user will supply three numbers okay

for which he wants to find average so

since the user has to supply three

numbers so our flow chart will be like

this will write

start

and after this because numbers have to

be supplied by the user so i will have

to input those numbers

input means numbers will be supplied by

the

user input suppose

ok i am just taking three variables n

one n two

and n three ok so

input n one comma n two comma n three so

i have taken three variables here

n one n two and n three ok

see whenever this program will get

executed at that time

three values will be supplied and first

value will be replacing

n1 second will be for n2 and third will

be for

n3 okay so once we have n1

n2 and n3 because in our program we are

assuming that our three numbers are n1

n2 and n3 at the same time we are

inputting inputting means whenever this

program will get

executed user will supply three values

for these three

n one n two and n three now

ah once we know and one in our program

we have assumed that numbers are n one

and two and

n three so what will be the sum

sum will be n one comma

sorry n one plus n two plus

n three this is quite simple

some will be n one plus n two plus n

three and what will be average

ok i am taking a variable avg for

average average

will be equal to sum divided by

3 and once we know the average

this will also be a rectangular box

because i am doing calculation once we

know the average then what will we do

we will print average because we were

supposed to

calculate average so now what are we

doing we are displaying it

print a v g so whatever is the value of

average that will be printed and then we

stop

ok now again same thing whenever this

program will get

executed at that time first of all

the user has to supply three values

user has to supply three values n1 n2

and n3 okay based on those three values

some will be calculated and after that

average will be calculated and then

average will be printed ok now i can

draw a smaller flowchart also

because these two things i can do in a

single line also

so like let me draw a smaller one start

ah input

n one comma n two comma

n three

i can directly calculate average a

v g is equal to n one plus

n 2 plus n 3

this whole divided by

3

ok since i am calculating so this will

be our rectangular box and after that i

am writing

print average

okay print average and then

i just a minute

and after that i stop

ok now what i have done i have done

these two things in a single line here

ok but

i should not write like this i should

not write ah

some of the students they write like

this they write

ah average is equal to

n 1 plus n 2 plus n 3

divided by 3 if they do like this then

only

n 3 will get divided by 3 okay some of

the students are doing it like this also

they write

average is equal to n 1 plus n 2

plus n 3 divided by 3

see this is not a computer statement

because in computer

see whatever language in whatever

language you are doing programming

you have to write in a single line so

here

first line second line third line so

this is not a valid computer statement

ok

so your entire expression should be in

continuity

so what is the right way of doing it i

have to write like this

average is equal to n 1 plus n 2

plus n 3 this whole

divided by 3 okay so these 2 are

wrong ok fine