Flowcharts Pseudocode

Flowchart Symbols
Different flowchart shapes have different conventional meanings. The meanings of some of the more
common shapes are as follows:

Terminator
The terminator symbol represents the starting or ending point of the system.

Process
A box indicates some particular operation.

Decision
A diamond represents a decision or branching point. Lines coming out from the diamond indicates
different possible situations, leading to different sub-processes.

Data
It represents information entering or leaving the system. An input might be an order from a customer.
Output can be a product to be delivered.

Flow
Lines represent the flow of the sequence and direction of a process.

Flowchart examples

Flowchart Example – Calculate sum of two numbers

Flowchart Example – Calculate Profit and Loss
The flowchart example below shows how profit and loss can be calculated.

PseudocodeReference Guide and Examples

CATEGORY Instruction Syntax EXAMPLE

Input READ READ variable READ num1
Output DISPLAY DISPLAY variable DISPLAY num1

Initialization SET SET variable TO value SET total TO 0

Computation COMPUTE COMPUTE variable AS
arithmetic expression

COMPUTE sum AS num1 +
num2

Increment/Decrement ADD
SUBTRACT

ADD value TO variable
SUBTRACT value FROM
variable

ADD 1 TO num1
SUBTRACT 1 FROM num1

Branching/Decisions IF-THEN IF Boolean condition THEN
instruction if true
ENDIF

IF x < 5 THEN DISPLAY “SMALL NUMBER” ENDIF

IF-THEN-ELSE IF Boolean condition THEN
instruction if true
ELSE
Instruction if false
ENDIF

IF temp > 90 THEN
DISPLAY “HOT”
ELSE
DISPLAY “NOT SO HOT!”
ENDIF

OPERATORS + – * / AND OR NOT < <= > >= == !=

Examples:

1. Add two numbers
READ num1
READ num2
COMPUTE sum AS num1 + num2
DISPLAY sum

2. Find the largest of three numbers
READ num1
READ num2
READ num3

IF num1 >= num2 AND num1 >= num3 THEN
DISPLAY num1
ELSE
IF num2 >= num1 AND num2 >= num3 THEN
DISPLAY num2
ELSE
DISPLAY num3
ENDIF
ENDIF

3. Change Fahrenheit temps to Celsius
READ fDegrees
COMPUTE cDegrees AS (fDegrees − 32) × 5/9
DISPLAY cDegrees

4. Determine total pay for work
READ hoursWorked
READ payPerHour
IF hoursWOrked <=0 OR payPerHour <= 0 THEN DISPLAY “error” ELSE COMPUTE totalPay AS hoursWorked * payPerHour DISPLAY totalPay ENDIF

5. Calculate and display area of Circle
READ radius
IF radius < = 0 THEN DISPLAY “error” ELSE CALCULATE area AS radius * radius * 3.14 DISPLAY area

ENDIF