Problem Solving: Pseudo code
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
output_number ← true
if i mod 3 equals 0
output "Bizz"
print_number ← false
if i mod 5 equals 0
output "Buzz"
print_number ← false
if print_number equals true
output i
output 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()
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Structured English
[edit | edit source]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 |
BEGIN |
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
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Exercise: Pseudocode What are the rules when writing pseudocode? Answer: There are no set rules, but the code should provide clear descriptions of the algorithms being outlined. What is the difference between pseudocode and a programming language such as javascript? Answer: Pseudocode cannot create executable code, whilst javascript can. For the following pseudocode write a VB.NET equivalent: for x from 1 to 7 inclusive
add x to total
loop
print total
Answer: dim total as integer = 0
for x = 1 to 7
total = total + x
next
console.writeline(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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