Pseudocode Examples

An algorithm is a procedure for solving a problem in terms of the actions to be executed

and the order in which those actions are to be executed. An algorithm is merely the
sequence of steps taken to solve a problem. The steps are normally "sequence," "selection,
" "iteration," and a case-type statement.

In C, "sequence statements" are imperatives. The "selection" is the "if then else"
statement, and the iteration is satisfied by a number of statements, such as the "while," "
do," and the "for," while the case-type statement is satisfied by the "switch" statement.

Pseudocode is an artificial and informal language that helps programmers develop

algorithms. Pseudocode is a "text-based" detail (algorithmic) design tool.

The rules of Pseudocode are reasonably straightforward. All statements showing

"dependency" are to be indented. These include while, do, for, if, switch. Examples below
will illustrate this notion.

Examples:

1.. If student's grade is greater than or equal to 60

Print "passed"
else
Print "failed"

2. Set total to zero

Set grade counter to one

While grade counter is less than or equal to ten

Input the next grade

Add the grade into the total

Set the class average to the total divided by ten

Print the class average.

3.

Initialize total to zero

Initialize counter to zero

Input the first grade

while the user has not as yet entered the sentinel

add this grade into the running total

add one to the grade counter
input the next grade (possibly the sentinel)

if the counter is not equal to zero

set the average to the total divided by the counter

print the average

else

print 'no grades were entered'

4.

initialize passes to zero

initialize failures to zero

initialize student to one

while student counter is less than or equal to ten

input the next exam result

if the student passed
add one to passes

else

add one to failures

add one to student counter

print the number of passes

print the number of failures

if eight or more students passed

print "raise tuition"

Some Keywords That Should be Used

For looping and selection, The keywords that are to be used include Do While...EndDo; Do
Until...Enddo; Case...EndCase; If...Endif; Call ... with (parameters); Call; Return ....; Return;
When; Always use scope terminators for loops and iteration.

As verbs, use the words Generate, Compute, Process, etc. Words such as set, reset, increment,
compute, calculate, add, sum, multiply, ... print, display, input, output, edit, test , etc. with careful
indentation tend to foster desirable pseudocode.

Do not include data declarations in your pseudocode.

Pseudocode
Definition - What does Pseudocode mean?

Pseudocode is an informal program description that does not contain code syntax or underlying
technology considerations. Pseudocode summarizes a program’s steps (or flow) but excludes
underlying details.

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Techopedia explains Pseudocode

To be pseudo is to be fake. In other words, something that is pseudo is pretending that to be

something it's not. Given this, the term pseudocode makes sense -- it isn't code, but it is the
starting point to what the code should look like.

System designers write pseudocode to ensure that programmers understand a software project's
requirements and align code accordingly. It can be anything from a few scribbles on a piece of
paper, to detailed designs using a modeling language.

Structured English is native English language used to write the structure of a program whereas,
Pseudo Code is more close to programming language.

Pseudocode is an informal high-level description of the operating principle of a computer

program or other algorithm. It uses the structural conventions of a programming language, but is
intended for human reading rather than machine reading. On the other hand, Structured English
is a limited form "pseudocode" and consists of the following elements: Operation statements
written as Eng...[ + ]

Structured English is native English language used to write the structure of a program module by
using programming language keywords, whereas, Pseudo Code is more close to programming
language and uses native English language words or sentences to write parts of code.

Programming Tools

During programming analysis and system design, the programmers, system engineers and system
designers work together to build a successful program or a computer-based information system.
Various ideas, components and program modules are integrated to accomplish the task.

System analysts and designers perform the following tasks during these steps.

1. Selection of programming language

2. Selection of the programming tools
3. Design and virtual testing of the program.

The programming tools give the idea how the flow should take place in order to accomplish a
task. Several programming tools are used in this context. Some of the most common
programming tools are:

1. Pseudo code
2. Algorithm
3. Flowchart

Pseudo code

Pseudo code is a combination of two words: Pseudo and Code. 'Pseudo' means imitation and
'code' refer to instruction written in the programming language. Pseudo code is not a real
programming code. It is the generic way of describing an algorithm without using any specific
programming language-related notations.

The features of pseudocode are:

 It uses plain english statements.

  It emphasizes on the design of the computer program.
 It uses structured english.
 It is detailed and readable to draw an inference.
 It enables the programmers to concentrate on the algorithms.

The pseudo code cannot be compiled. It cannot be executed and there are no real formatting or
syntax rules for writing pseudo codes.

It is simply an important step in producing the final code. Some important terms used in pseudo
code for different activities are:

 Input: Read, Obtain, Get and Prompt

 Output: Print, Display, and Show
 Computer: Computer, Calculate, and Determine
 Initialize: Set and Initialize
 Add one: Increment

The two major constructions in pseudo code structures are: Sequence and Selection (decision).
Sequence indicates the continuous flow of the program, whereas selection uses logical
comparison or conditional check for making decisions.

Example:

……………

IF (condition> THEN

List of Actions

ELSE

List of Different Actions

END IF

………………

…………………

Example:

READ A, B, AND C

IF A is greater than C
THEN
DISPLAY A

ELSE

DISPLAY C

END IF

ELSE

IF B is greater than C
THEN

DISPLAY B

ELSE

DISPLAY C

END IF

END IF

STOP

Example:

INITIALIZE Count to zero

DO WHILE Count is greater than or equal

to 10

ADD 1 to Count

PRINT Count

ENDDO

STOP

Advantages of Pseudo code:

1. Since, it is language independent, it can be used by most programmers.

2. It helps to design in plain natural language.
3. It is easier to develop the program from pseudo code than with a flowchart.
4. It is easy to translate to the programming language.
 5. Its simple structure and readability makes it easier to modify as well.

Disadvantages of Pseudo code:

1. It does not provide the visual representation of the program logic.

2. There are no accepted standards for writing pseudo code.

Algorithm

An algorithm is defined as a finite sequence of explicit instructions that produces an output with
the set of input values. The steps in the algorithm are never ambiguous. It terminates after a finite
number of steps.

Algorithms can have repetitions and logical decisions until a specific task is completed.
Algorithms are not computer programs. They cannot be executed by the computer.

Properties of Algorithm

An algorithm must have the following properties.

1. There should not be any ambiguity in instructions.

2. The instructions should be specific to the task.
3. The description of an algorithm must be finite. It cannot be open-ended.
4. The algorithm must be general enough for writing programs.
5. As far as practicable, program codes should not be included in algorithms.

Example: Write an algorithm to make a telephone call.

Step 1: Remember or read the telephone number.

Step 2: Lift the receiver

Step 3: Is there a dial tone?

If yes, then dial telephone, go to step 4.

{ If no, then put down the receiver.

Go to step 2}

Step 4: Speak

Step 5: Put down the receiver.

Example: Write an algorithm to find the largest number among three input numbers.
Step 1: Start

Step 2: Read 3 numbers say: A, B, C

Step 3: Find the largest number between A and B and store it in

MAXAB

Step 4: Find the largest number between MAXAB and C and store
it in MAX

Step 5: Display MAX

Step 6: Stop

Write the algorithm to calculate the interest on principle amount in N number of Years.

Step 1: Start

Step 2: Read principle, Rate and

Time

Step 3: Multiply principle * Rate *

Time

Step 4: Divide by 100

Step 5: Write the answer

Step 6: Any more calculations?

{ If yes, then go to step 2

If No }

Step 7: Stop

Write algorithm to calculate the total and average marks of 10 students for 7 subjects.

Step 1: Start

Step 2: Subject = 1

Step 3: Input mark for this Subject

Step 4: Add marks and store into a variable

Step 5: Are all subjects (7 subjects) done?

{ If No, then increase the subject number and go to

step 3.

If yes, then go to step 6

Step 6: Print the sum

Step 7: Find average (divide by 7)

Step 8: Print the sum and average

Step 9: Are all (10 students done)?

{ If No, then increase the student number and go to

step 2

If yes, then go to step 9}

Step 9: End

Pseudocode is essentially writing in a high-level language without worrying about the details.
Usually variable and function declarations are left out, the details of certain constructs may be
elided. For example, if you’re writing C-like pseudocode, you may ignore the details of for (),
simply writing something like:

1. for i=1 to j {
2. // code here
3. }

It’s primarily meant as a tool for programmers: a way to start writing out program logic without
immediately getting into the gritty details. Often, though, since programmers dislike waste, the
pseudocode may be placed into files commented out, and fleshed out over time. This avoids
rewriting things that have already been written in pseudocode, and is a reason to keep one’s
pseudocode close to the actual language to be used.

Structured English is meant to be used for program design, particularly when working with non-
programmers. As such, it’s not meant to be close to any particular programming language.
Structured English guides recommend keeping to simple concepts: for example, using loops even
when one might actually prefer to implement with recursion in reality. Blocks of logic are
indicated by indenting, and sometimes by surrounding them with blank lines; things like brackets
or braces are not used. Mathematical notation is generally avoided, favoring descriptive text. To
take an example from Davis and Yen’s Information System Consultant’s Handbook:
 1. IF stock-on-hand is less than reorder-point
2. THEN turn on reorder-flag
3. ELSE (stock-on-hand is not less than reorder-point)
4. SO turn off reorder-flag.

Writing this in pseudocode, it would more closely resemble an actual programming language.
For example, for a C++-like pseudocode:

1. if ( item.stockOnHand() < item.reorderPoint() ) {

2. item.setReorderFlag(true);
3. } else {
4. item.setReorderFlag(false);
5. }

The latter might end up being part of the actual code of the system; the former could not.