Grade 10 flowcharting

Introduction to
Flowcharting
Grade 10- ICT

What is a Flowchart?
• A flowchart is a
diagram that depicts
the “flow” of a
program.
• The figure shown here
is a flowchart for
calculating the age.
START
Display message
“Enter the
present year”
Read Present
year
Display message
“Enter your year
of birth”
Read Year of
birth
Age = Present
year – Year of
birth
Display Age
END

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.
Rounded
Rectangle
Parallelogram
Rectangle
Rounded
Rectangle
START
Display message
“Enter the
present year”
Read Present
year
Display message
“Enter your year
of birth”
Read Year of
birth
Age = Present
year – Year of
birth
Display Age
END

• Terminals
– represented by rounded
rectangles
– indicate a starting or
ending point
Terminal
START
END Terminal
START
Display message
“Enter the
present year”
Read Present
year
Display message
“Enter your year
of birth”
Read Year of
birth
Age = Present
year – Year of
birth
Display Age
END

• Input/Output Operations
– represented by
parallelograms
– indicate an input or
output operation
Enter Present
year Display Age
Input/Output
Operation
START
Display message
“Enter the
present year”
Read Present
year
Display message
“Enter your year
of birth”
Read Year of
birth
Age = Present
year – Year of
birth
Display Age
END

• Processes
– represented by rectangles
– indicates a process such as
a mathematical
computation or variable
assignment
Age = Present
Year- Year of
Birth
Process
START
Display message
“Enter the
present year”
Read Present
year
Display message
“Enter your year
of birth”
Read Year of
birth
Age = Present
year – Year of
birth
Display Age
END

Stepping Through
the Flowchart
Enter the
present
year:
Variable Contents:
Present Year: ?
Year of Birth: ?
Age: ?
Output
Operation
Stepping Through
the Flowchart
START
Display message
“Enter the
present year”
Read Present
year
Display message
“Enter your year
of birth”
Read Year of
birth
Age = Present
year – Year of
birth
Display Age
END
Variable - a data item that may take on more than one value
during the runtime of a program.

Stepping Through
the Flowchart
Enter the
Present
Year: 2016
Input Operation
(User types 2016)
Stepping Through
the Flowchart
START
Display message
“Enter the
present year”
Read Present
year
Display message
“Enter your year
of birth”
Read Year of
birth
Age = Present
year – Year of
birth
Display Age
END
Variable Contents:
Present Year: 2016
Year of Birth: ?
Age: ?

Stepping Through
the Flowchart
Enter your
Year of
birth:
Output
Operation
Stepping Through
the Flowchart
START
Display message
“Enter the
present year”
Read Present
year
Display message
“Enter your year
of birth”
Read Year of
birth
Age = Present
year – Year of
birth
Display Age
END
Variable Contents:
Present Year: 2016
Year of Birth: ?
Age: ?

Stepping Through
the Flowchart
Enter your
Year of
Birth: 1990
Input Operation
(User types 1990)
Stepping Through
the Flowchart
Variable Contents:
Present Year: 2016
Year of Birth: 1990
Age: ?
START
Display message
“Enter the
present year”
Read Present
year
Display message
“Enter your year
of birth”
Read Year of
birth
Age = Present
year – Year of
birth
Display Age
END

Process: The
difference of
2016 and
1990 is 26
which is
stored as Age
Stepping Through the
Flowchart
START
Display message
“Enter the
present year”
Read Present
year
Display message
“Enter your year
of birth”
Read Year of
birth
Age = Present
year – Year of
birth
Display Age
END
Variable Contents:
Present Year: 2016
Year of Birth: 1990
Age: 26
Enter your
Year of
Birth: 1990

Stepping Through
the Flowchart
Age is 26
Output
Operation
START
Display message
“Enter the
present year”
Read Present
year
Display message
“Enter your year
of birth”
Read Year of
birth
Age = Present
year – Year of
birth
Display Age
END
Variable Contents:
Present Year: 2016
Year of Birth: 1990
Age: 26

Sample Problems:
1. Create a flowchart that will get the sum of two integers.
2. Create a flowchart that will convert a peso to dollar.
Exchange rate is $. 1.00 = Php. 45.00 (fixed)

Exercise Problems:
1. Create a flowchart that will convert a Celsius value to
Fahrenheit.
F= C * 9/5 +32
2. Create a flowchart that will get the Average of three
integers.

Four Flowchart Structures
• Sequence
• Decision
• Repetition
• Case

Sequence Structure
• a series of actions are performed in sequence
• The pay-calculating example was a sequence
flowchart.

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

Decision Structure
• 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

Decision Structure
• In the flowchart segment below, the question “is x < y?” is
asked. If the answer is no, then process A is performed. If the
answer is yes, then process B is performed.
YESNO
Is
x < y?
Process BProcess A

Sample Problem
1. A flowchart that will identify the grade
entered by the user. If the grade is 75 and
above, system will display "You Passed", if not,
system will display "You Failed".

Sample Problem
2. Create a flowchart that will ask for the total
price purchased by a customer from a
department store. If the total price is Php500
and above, customer is entitled for a 30%
discount which will also be computed and
displayed on the system, otherwise "You are not
entitled for the discount" message should be
displayed.

Practice Exercise
1. A flowchart that will ask for a password of the computer. The correct
password is "Tamaraw". If the password is correct, "Welcome to Grade
10-Tamaraw" will be displayed, otherwise, "Access Denied".
2. There are only two kinds of employee in a company "Full Time" and "Part
Time". Create a flowchart that will compute for the weekly salary of an
employee.
For "Full Time" employees:
weekly salary = monthly salary / 4
For "Part Time" employees:
weekly salary = hourly rate * 25

Decision Structure
• The flowchart segment below shows how a decision structure
is expressed in C++ as an if/else statement.
YESNO
x < y?
Calculate a
as x times 2.
Calculate a
as x plus y.
if (x < y)
a = x * 2;
else
a = x + y;
Flowchart C++ Code

Decision Structure
• The flowchart segment below shows a decision structure with
only one action to perform. It is expressed as an if statement
in C++ code.
if (x < y)
a = x * 2;
Flowchart C++ Code
YESNO
x < y?
Calculate a
as x times 2.

Repetition Structure
• A repetition structure represents part of the program that
repeats. This type of structure is commonly known as a loop.

• Notice the use of the diamond symbol. A loop tests a
condition, and if the condition exists, it performs an action.
Then it tests the condition again. If the condition still exists,
the action is repeated. This continues until the condition no
longer exists.

• In the flowchart segment, the question “is x < y?” is asked. If
the answer is yes, then Process A is performed. The question
“is x < y?” is asked again. Process A is repeated as long as x is
less than y. When x is no longer less than y, the repetition
stops and the structure is exited.
x < y? Process A
YES

• The flowchart segment below shows a repetition structure
expressed in C++ as a while loop.
while (x < y)
x++;
Flowchart C++ Code
x < y? Add 1 to x
YES

Controlling a Repetition Structure
• The action performed by a repetition structure must
eventually cause the loop to terminate. Otherwise, an infinite
loop is created.
• In this flowchart segment, x is never changed. Once the loop
starts, it will never end.
• QUESTION: How can this
flowchart be modified so
it is no longer an infinite
loop?
x < y? Display x
YES

Controlling a Repetition Structure
• ANSWER: By adding an action within the repetition that
changes the value of x.
x < y? Display x Add 1 to x
YES

A Pre-Test Repetition Structure
• This type of structure is known as a pre-test repetition
structure. The condition is tested BEFORE any actions are
performed.
YES

A Pre-Test Repetition Structure
• In a pre-test repetition structure, if the condition does not
exist, the loop will never begin.
YES

A Post-Test Repetition Structure
• This flowchart segment shows a post-test
repetition structure.
• The condition is tested AFTER the actions
are performed.
• A post-test repetition structure always
performs its actions at least once.
Display x
Add 1 to x
YES
x < y?

A Post-Test Repetition Structure
• The flowchart segment below shows a post-test repetition
structure expressed in C++ as a do-while loop.
do
{
cout << x << endl;
x++;
} while (x < y);
Flowchart
C++ Code
Display x
Add 1 to x
YES
x < y?

Case Structure
• One of several possible actions is taken, depending
on the contents of a variable.

Case Structure
• The structure below indicates actions to perform
depending on the value in years_employed.
CASE
years_employed
1 2 3 Other
bonus = 100 bonus = 200 bonus = 400 bonus = 800

Case Structure
CASE
years_employed
1 2 3 Other
bonus = 100 bonus = 200 bonus = 400 bonus = 800
If years_employed = 1,
bonus is set to 100
bonus is set to 200
bonus is set to 400
If years_employed is
any other value, bonus
is set to 800

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

Connectors
A
ASTART
END
•The “A” connector
indicates that the second
flowchart segment begins
where the first segment
ends.

Modules
• A program module (such as a function in C++)
is represented by a special symbol.

Modules
•The position of the module
symbol indicates the point the
module is executed.
•A separate flowchart can be
constructed for the module.
START
END
Read Input.
Call calc_pay
function.
Display results.

Combining Structures
• Structures are commonly combined to create more complex
algorithms.
• The flowchart segment below combines a decision structure
with a sequence structure.
YES

Combining Structures
• This flowchart segment
shows two decision
structures combined.
Display “x is
within limits.”
Display “x is
outside the limits.”
YESNO
x > min?
x < max?
YESNO
Display “x is
outside the limits.”

Review
• What do each of the following symbols
represent?
(Answer on next slide)

Answer
• What do each of the following symbols
represent?
Terminal
Input/Output
Operation
Process
Decision
Connector
Module

Review
• Name the four flowchart structures.

Answer
• Sequence
• Decision
• Repetition
• Case

• What type of structure is this?
Review

Grade 10 flowcharting

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Grade 10 flowcharting