Java Programming Tutorial - 21 - Simple Averaging Program Video Lecture

what's up guys welcome to your 21st
tutorial and in this tutorial I'm going
to be building a simple application to
average a bunch of numbers together now
we already learn all the basic tools but
we haven't really seen how to combine
them all and build a simple program so
that's what I'm going to be teaching you
guys in this story again what I'm going
to be doing is inputting ten numbers
into the program and it's going to give
me the average so the first thing we
need to input numbers is the scanner so
let's go ahead and import it again
that's dropping UT il scanner and this
allows us to import the scanner but we
also need to create an object so we can
use it after we imported it so let's go
ahead and make scanner input you can
name it anything you want a new scanner
with a parameter of system in and don't
forget our system in is the keyboard so
that's why we have that now that we have
a scanner we can use we can begin making
the variables we need for this program
so let's go ahead and make int total
equal to zero and this is going to be
the total of all the numbers let's say
we're inputting grades say we're like a
teacher in importing grades so next we
need another one called int grade and
this is going to be the grade we enter
we have a next one called an average and
this is going to be after everything is
done we're going to average them all
together so we need a variable for that
and we also need the last one that's
encounter and we're going to set that
equal to zero because we want to make
sure our counter starts at zero and I'll
show you what that counter variable is
right here when we're building our while
loop the counter variable is just on the
counter for the while loop so you're
going to say while counter is less than
10 so this while loop is going to
execute ten times on but what do we want
to do ten times well since we're
importing or inputting ten numbers
we're going to want to put grade equals
input next excuse me you need aa census
object next int with empty parameters
and what this does is this it allows
whatever number you input be stored in
the variable grade
so say you inputted a three grade is now
going to be equal to three but that's
not very useful unless we can add it to
the total so we can average it later
later so now we have total equals total
plus grade and what this does is take
that grade and add it to the total of
whatever it was before and if you're
saying all right how come you don't just
put total equals grade because if you
had um like 30 in this before
it will now be equal to three and you
want to add it to that 30 so it would be
equal to 33 so that's what that does now
you just need to do spell that right
counter plus plus and this will
increment
okay you're cuckoo counter each time so
it actually goes through the loop so
here's what we have going on right now
we inputted a grade we added that grade
to total whatever it was before and then
we added one so we can actually get out
of this loop now we have a while loop
what we need to do is find the average
of the total so let's go ahead and write
average equal total over ten and we know
that it's ten because that's how many
numbers we entered and now that we have
our average calculated let's just output
it on the screen so system.out.print
line and let's put something like your
average is plus average so let's go
ahead and run this and see how many
errors I got and if nothing pops up in
the run box then you know you're good to
go
so let's go ahead and enter ten numbers
one two three four five six seven eight
nine and ten and it says your average is
five which it should be one through five
average I mean excuse me 1 through 10
average is 10
so let me show you guys one last time
how this simple program works this and
this is just a scanner what you should
know allows you to input numbers you now
have four variables the total holds the
sum of all the grades the grade allows
you to import numbers individually
average is going to be used later to
average them all together and this is
just a counter variable for the wallet
which you should know what it does next
you put input next in it's going to be
temporarily stored in grade and it's
only temporarily because you change it
with each loop this total keeps a
running tally of all the grades you
entered so total equals the old total
plus the new grade so this gives you a
new total each time that keeps adding
and adding up after you have ten grades
entered you take the average of the
total which is the sum of all the grades
and divided by ten and after all of that
you just give the user a nice little
prompt the average is and it gives you
the average so again this is how you can
build a simple program using the tools
we have thus far and again you can add
some if statements in here if you want
says if grade is less than four do this
if grade is higher than five to that
bump we'll get to that later I want to
teaching you some more advanced stuff
before that so again that's how you
build a basic program I know you guys
were it should build something so there
you go thank you guys for watching don't
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and I'll see you next tutorial