Pseudocode - informal high-level description of a computer program or other algorithm, intended for human reading rather than machine reading.
Pseudocode uses a combination of programming terminology and plain English to describe algorithms in a form that is easier for people to understand than conventional programming language code. There are no standards for pseudocode and a program in pseudocode is not an executable program. Psuedocode is used in textbooks and scientific publications to describe various algorithms, and also in planning of computer program development, for sketching out the structure of the program before the actual coding takes place. It typically leaves out details that are not essential for human understanding of the algorithm, such as variable declarations, system-specific code and some subroutines.
Example: Pseudocode
Below is an example of a pseudocode algorithm
For i = 1 to 100 set print_number to true if i mod 3 equals 0 print "Bizz" and set print_number to false if i mod 5 equals 0 print "Buzz" and set print_number to false if print_number is true, print i print a newline
Converting this into VB.NET, we get:
dim print_number as boolean For i = 1 to 100 print_number = true if i mod 3 = 0 then console.writeline("Bizz") print_number = false end if if i mod 5 = 0 then console.writeline("Buzz") print_number = false end if if print_number then console.writeline(i) end if console.writeline() |
[edit]Structured English
Structured English - A restricted part of the English language used to describe algorithms
Structured English is very similar to Pseudo code, but it tends not to use so many mathematical symbols. Often people start with Structured English, convert it to Pseudo Code and then write Executable Code. Examples of common keywords:
START, BEGIN, END, STOP, DO, WHILE, DO WHILE, FOR, UNTIL, DO UNTIL, REPEAT, END WHILE, END UNTIL, END REPEAT, IF THEN, IF, ELSE, IF ELSE, END IF, THEN, ELSE THEN, ELSE IF, SO, CASE, EQUAL, LT, LE, GT, GE, NOT, TRUE, FALSE, AND, OR, XOR, GET, WRITE, PUT, UPDATE, CLOSE, OPEN, CREATE, DELETE, EXIT, FILE, READ, EOF, EOT, WITH, RETURN
Structured English | Pseudo Code | Executable Code |
---|---|---|
BEGIN READ name IF name EQUAL "Harry" THEN WRITE "Why don't you marry Pippa?" ELSE WRITE "Are you Royal enough?" END IF END | BEGIN INPUT name IF name == "Harry" THEN OUTPUT "Why don't you marry Pippa?" ELSE OUTPUT "Are you Royal enough?" END IF END | dim name as string name = console.readline() if name = "Harry" then console.writeline("Why don't you marry Pippa?") else console.writeline("Are you Royal enough?") End if |
Exercise: Pseudocode
What are the rules when writing pseudocode?
What is the difference between pseudocode and a programming language such as javascript?
For the following pseudocode write a VB.NET equivalent:
for x from 1 to 7 inclusive add x to total loop print total
Write pseudocode for the following problem:
Find the average of 4 numbers and display it
Answer :
There are many ways to answer this correctly as long as it is clear you got it right. Ask your friend to check it.
input 4 numbers sum = add numbers together avg = sum / 4 print avg |
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