1. Numbering System TODAY AND TOMORROW 11th Edition
Understanding Computers, 11th Edition 1

2. What is a “Flow Chart?”
a visual tool that helps you understand the flow of your program
You can think of flow charts as pipes of water:
You pour water in the top.
Water pours through the pipes and is pulled downward
Chapter Understanding Computers, 11th Edition

3. Flowchart Based Design
Chapter Understanding Computers, 11th Edition

4. Flow Chart Basics 1 Diamonds (decision symbol)
contain
conditions
Rectangles represent statements of work. For example:
printf()
flow
line
Chapter Understanding Computers, 11th Edition

5. Flow Chart Basics 2 Connector symbol grade >=65 true print “passed”
false
Chapter Understanding Computers, 11th Edition

6. if/else Flow Chart True False grade >=65 Print “You failed”
True
False
grade >=65
Print “You failed”
Print “You passed”
Chapter Understanding Computers, 11th Edition

7. Flowcharts Represent flow of control of algorithms: sequences
selection
iteration
Useful for:
Finding semantic errors
Determining test data set
Use of Flowcharts
Pseudo-code  flowchart
Flowchart  code
Chapter Understanding Computers, 11th Edition

8. Represented by concatenating instructions (usually vertically)
Flowchart: Sequence
Represented by concatenating instructions (usually vertically)
Instruction
in rectangular
box
Step A: input number
Step B: add 1 to number
Order of execution
indicated by arrows
Step C: output number
Chapter Understanding Computers, 11th Edition

9. Sequence (cont) Example 2: Step A: input number an algorithm involving
“selection”
Step A: input number
Step C: output number
Example 2:
Step A: input number
Step B:
if number is negative,
then add -1 to number
else add 1 to number
Step C: output number
Chapter Understanding Computers, 11th Edition

10. Flowchart: Selection Step A C1 true? S2 Step C S1 YES NO Arrow labeled
with result of
condition test
Condition
test
in diamond
Step A
C1 true? S2
Step C S1
Step A
if ( condition C1 ) {
<sequence S1> }
else
<sequence S2>
Step C
YES NO
Chapter Understanding Computers, 11th Edition

11. Example: Algorithm to Flowchart
input number
is number
negative?
add -1 to number
YES NO
add 1 to number
output number
input number
if number is negative,
then add -1 to number
else add 1 to number
output number
Chapter Understanding Computers, 11th Edition