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Get started with pseudocode. Learn some basic conventions for describing a program with input, output, and variables.
Examples
Simple sequence
prompt user for number
set num1 to user_input
prompt user for number
set num2 to user_input
set sum to num1 + num2
print sum
Using a conditional statement
prompt user for number
if input is not a number
print "input is not a number"
prompt user for new number
endif
set num1 to user_input
prompt user for number
if input is not a number
print "input is not a number"
prompt user for new number
endif
set num2 to user_input
set sum to num1 + num2
print sum
Multiple conditions
if input is not a number
print "this is not a number"
else if input is odd
print "the number is odd"
else the input is even
print "the number is even"
endif
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Pseudo code expresses code logic in
procedures using plain verbs and
0:00
nouns from spoken language.
0:04
When you write pseudo code,
you explain each step in the program.
0:05
Think of it kinda like a recipe.
0:09
A program usually has some data,
or ingredients,
0:10
that are acted upon just like you peel,
mix, whisk, eat and bake while cooking.
0:12
A recipe lists the exact order
in which to perform each step.
0:18
If you bake, for
0:21
example, before you mix the batter,
your cake won't turn out right.
0:22
You can write pseudo code on paper with
a pen, or open up a text editor and
0:26
use code comments to describe your
program's logic in pseudo code.
0:30
Let me walk you through an example.
0:34
For any programming project, we usually
start with a set of requirements.
0:36
These requirements,
like a set of instructions,
0:40
tell you how the program should perform.
0:42
They'll often want some input, like
retrieving two numbers from a user and
0:44
some kind of output like the result
of adding those two numbers together.
0:48
You can use those requirements to
guide the design of your program and
0:52
the pseudo code you write.
0:55
In this example,
we'll take a simple specification and
0:57
convert it into programming
steps using pseudo code.
1:00
If you'd like to follow along, open the
work space associated with this video, and
1:03
the file print underscore sum dot txt.
1:07
[SOUND] Get two integer values from a user
and output the sum of those numbers.
1:09
In other words, get two numbers,
add them together and output the results.
1:16
The requirement is simple, but
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a program would need to perform
several steps to complete the task.
1:23
First, you need to prompt
the user to type a number.
1:27
That's one step.
1:30
Then you create a variable
to store the input.
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Prompt for another number, store that
number in a variable named num2.
1:36
Create another variable with
the sum of the two values.
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And finally,
print the value inside the sum variable.
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That's an example of pseudo code.
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It reads easily and
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could be used by a programmer
coding in any programming language.
1:52
This example is simple, but
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you can use pseudo code to
describe any programming concept.
1:58
For example, here's how you could add
a conditional statement to make sure
2:01
the input from the user was a number and
not a letter.
2:04
Here, I've added conditional statements to
check and see if the input is a number.
2:07
Notice that I've added indentation
to show the code that runs
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inside the conditional statement.
2:14
In other words, if that condition is true,
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then the steps that
are indented would happen.
2:18
To mark the end of a conditional
statement add endif.
2:21
This makes clear where the condition ends
and the rest of the program continues.
2:24
You can easily create conditional
statements with multiple conditions too.
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Pseudo code is simple and straightforward.
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You can easily see the logic and
you never get a syntax error.
2:35
In the next video,
I'll show you pseudo code for
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describing other programming
concepts like loops and functions.
2:40
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