PSEUDOCODE AND FLOWCHART
Pseudocode (pronounced SOO-doh-kohd)
 is a detailed yet readable description of what a
computer program or algorithm must do,
expressed in a formally-styled natural language
rather than in a programming language.
Pseudocode is sometimes used as a detailed step
in the process of developing a program. It allows
designers or lead programmers to express the
design in great detail and provides programmers
a detailed template for the next step of writing
code in a specific programming language.
Sample 1
 Election Control Structures
If age > 17
Display a message indicating you can vote.
Else
Display a message indicating you can't vote.
End
Sample 2
 Iteration (Repetition) Control Structures
count assigned zero
While count < 5
Display "I love computers!"
Increment count
End while
Sample 3
 Pseudo-code the task of computing the final
price of an item after figuring in sales tax.
 Note the three types of instructions: input (get),
process/calculate (=) and output (display)
 Note that the operations are numbered and each
operation is unambiguous and effectively
computable. We also extract and list all variables
used in our pseudo-code. This will be useful when
translating pseudo-code into a programming
language
Computing Sales Tax
1.
2.
3.
4
5.
6.
get price of item
get sales tax rate
sales tax = price of time times sales tax rate
final prince = price of item plus sales tax
display final price
end
Variables: price of item, sales tax rate, sales tax, final price
Sample 4
 Computing Weekly Wages
 Gross pay depends on the pay rate and the
number of hours worked per week. However,
if you work more than 40 hours, you get paid
time-and-a-half for all hours worked over 40.
Pseudo-code the task of computing gross pay
given pay rate and hours worked.
Code
1.
2.
3.
get hours worked
get pay rate
if hours worked ≤ 40 then
3.1 gross pay = pay rate times hours worked
4.
else
4.1 gross pay = pay rate times 40 plus 1.5 times pay rate
times (hours worked minus 40)
5.
display gross pay
6.
halt
variables: hours worked, ray rate, gross pay
This example introduces the conditional control structure. On the basis of the true/false question asked in line 3, we execute line 3.1 if the
answer is True; otherwise if the answer is False we execute the lines subordinate to line 4 (i.e. line 4.1). In both cases we resume the
pseudo-code at line 5.
Flowchart
 A flowchart is a diagrammatic representation that illustrates
the sequence of operations to be performed to get the
solution of a problem. Flowcharts are generally drawn in the
early stages of formulating computer solutions. Flowcharts
facilitate communication between programmers and business
people. These flowcharts play a vital role in the programming
of a problem and are quite helpful in understanding the logic
of complicated and lengthy problems. Once the flowchart is
drawn, it becomes easy to write the program in any high level
language. Often we see how flowcharts are helpful in
explaining the program to others. Hence, it is correct to say
that a flowchart is a must for the better documentation of a
complex program.
Basic Symbols
Rounded box - use it to represent an event which occurs
automatically. Such an event will trigger a subsequent action, for
example `receive telephone call’, or describe a new state of
affairs.
Rectangle or box - use it to represent an event which is
controlled within the process. Typically this will be a step or
action which is taken. In most flowcharts this will be the most
frequently used symbol.
Diamond - use it to represent a decision point in the process.
Typically, the statement in the symbol will require a `yes' or `no'
response and branch to different parts of the flowchart
accordingly.
Circle - use it to represent a point at which the flowchart
connects with another process. The name or reference for the
other process should appear within the symbol.
GUIDELINES FOR DRAWING A FLOWCHART
 Flowcharts are usually drawn using some standard
symbols; however, some special symbols can also be
developed when required.
Start or end of the program
Computational steps or processing function of a program
Input or output operation
Decision making and branching
Connector or joining of two parts of program
Magnetic Tape
Off-page connector
Flow line
Annotation
Display
Draw a flowchart to find the largest of
three numbers A,B, and C.
Draw a flowchart to find the sum of first
50 natural numbers.