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Writing the JavaScript Code
5:12Follow along as we translate pseudocode to functioning JavaScript code.
[MUSIC]
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Hopefully you tried to solve
this challenge yourself,
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based on the previous
step in this workshop.
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If not, you can follow along with me.
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I'll translate this
pseudocode into working code.
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I'll use JavaScript in this example.
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But pseudocode is simply
the outline of a program steps.
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So it can be translated to
any programming language.
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Open the workspace associated with
this video in the gpa.js file.
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This is a JavaScript file, and
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you'll notice that it has the pseudo
code added as code comments.
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First, I'll create the function
structure with opening function name,
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calculated GPA in a parameter
named student_grades.
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A closing brace marks
the end of a function.
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Now I'll create a new variable to
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store the number of grades
passed into the function.
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I'll call it grade_total and
set the initial value to 0.
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This value will change as the loop
indicated here in the pseudocode runs.
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We're using JavaScript here, so the grades
will be kept in an array that are stored
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in the parameter student_grades.
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To get the total number of items in
an array, you use the length property.
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I'll use a for loop here,
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but there are many ways to iterate
through items in an array in JavaScript.
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You may have come up with a totally
different approach and that's fine.
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Now within the loop, we need to
test the values to make sure they
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fall within the range
of allowable numbers.
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I'll create a new variable and
store the current grade from the array.
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Remember, you use a numeric index
to access an item in an array.
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So in this case, the first time
through the loop, the value of i is 0.
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So student_grades 0 would be
the first number in the array.
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I'll start with a simple condition that
looks at the current grade in the loop.
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If the value is below 1 or
above 4, then it's invalid and
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will output some messages to the console.
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We'll print the text invalid
grade plus the grade and
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then we'll return can't complete
calculation and that exits the function.
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If the grade is valid,
then it's added to the total.
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This loop will run once for each grade
in the array passed to the function
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Once the loop is done, We'll calculate
the grade point average, which
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is the total of all of the grades divided
of the number of grades in the array.
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We return that value which
exists the function.
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Now, a function doesn't do
anything until its called.
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So let me create an array of grades.
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Then we can log the results of
calling that function to the console.
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I can see if the program works by
going into the console here and
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using node js to run the program.
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First, let me save this file.
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Go to the Console and type node space and
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then the name of the file gpa.js.
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If you see the number 3.75,
then it's working.
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Let's see what happens if I
change one of the grades to -2.
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You can now see the error messages
because that grade isn't valid.
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You can finish off the requirements
simply by copying and
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pasting this code down here and
making the changes that are necessary.
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I'll let you do that.
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One thing is after I've
written my program,
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I don't need the pseudocode anymore,
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so I can go through and clean it up.
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I'll save this in it one more time
just to make sure it's working
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And there you have it,
from pseudocode to JavaScript.
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You can find my finished working code
listed in the teachers notes below,
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as well as a link to other
pseudocode resources.
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Have fun programming.
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