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alright guys, welcome back to your fifth C plus plus tutorial and in this tutorial
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since we now have the knowledge of variables
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within c plus plus let's put that knowledge to use. So let's go ahead and
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make three variables right now.
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but, I'm gonna be making them a little bit different than before
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So in last tutorial we had a variable like a
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and we set it equal to the value like 54. simple enough
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but I want to tell you guys that whenever you first create a variable
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you have the option of assigning the value then
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or assigning the value later on such as a
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equals 54 this is perfectly fine thing you can do this way
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so whenever you first create a variable
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and don't assign a value this is called declaring the variable.
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declaring is just another name for creating the variable
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so let's go ahead and create three variables and by the way I'm gonna be
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making a basic computer program
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where the user enters two numbers such as like to
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in 3 and the computer is gonna add them together
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and it's going to give an answer which would be five so
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int a. I'm gonna have a variable called a and I am going to have another
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variable called
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b and what we're gonna be doing is we're calculating the sum.
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or in other words when you add the two numbers together the answer
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of that and storing it in a variable called sum. so we don't have any
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values yet so that's why we can't fill 'em in. the users can be answering the values
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for us
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so the first thing we want to make in this program is just a little prompt on
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screen to tell the user to enter number
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and you do that using cout and we just write 
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"enter a number hoss" and then let's go ahead and write new line
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and now we need a way for the user actually
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to input information from the keyboard so
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here's a neat little thing I can tell you. cout
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 took information from your computer and output it to the screen,
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but anytime you want to take information from the computer,
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excuse me, from the user and give it to the computer
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you need to use c-i-n, so cout basically takes information
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from the computer gives it to the user cin
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takes information from the user in gives it to computer
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so if you wrint c-i-n and and by the way if you take a test
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this is technically called the InputStream object
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and the little greater and greater than sign
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is called the stream exaction, [pause] extraction operator
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so you know make sure to fill that on your multiple choice if you're watching
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this
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in the C++ class or something so anyways you can see that this is
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different from the cout for two reasons. First of all it's
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cin. instead of cout and also
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your arrows face the opposite way. that's because you're giving information
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to the computer instead of the computer giving information to you
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so now all we can do is we're gonna enter a number
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and whatever number we enter, we need to give a place to store that
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number
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what we already have a variable right here so let's go ahead and use that
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in use the variable a. so check this out its gonna allow us to enter
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enter number and whatever number we enter it's gonna be stored in the
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variable
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a. so for example if we entered the number three
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a is going to be equal to 3. simple enough so now that we have that variable
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taken care of we basically
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need to do the same thing again with other variable be
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so see out will say
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answer another number and
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just go ahead and which make a new line to make the program easier to read
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and use that CNN but now an answer number we want that
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value to be equal to the variable be so they're gonna answer to numbers
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ones can be equal to A+ the others can be equal to be
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son now for the summer we don't want them to
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you know enter value for some we want to calculate their selves
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so in order to do the edges go Henry some because
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a plus be an hour
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arc your programs can do is can say re: I'm gonna grab
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vere excuse now I'm gonna grab the value put in for a
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am gonna grab the value plan for be am going to calculate that
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am gonna store that in the variable some so for example if you wrote 10
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in 15 its gonna say are a crap 10 graph 15
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calculate the sum a bit which is 25 story in a variable
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called some so now the some
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is equal to the answer and all we have to do now is pray now on screen so see
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out
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on which is straight some all those
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numbers is is it the summer those numbers
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are for some those numbers is I think it's is because it's one song
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and again anytime you want to add more
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than one line of text you could do it like this on you could hear a a new line
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and then print this out on another line but I one at on the same I so I'm gonna
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go ahead
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and add another insertion operator just like that
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and just go ahead and write some and then
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at another one disco Henry en ligne to sharper and looks nice in name
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so basically well let me go ahead and run this out I kester after a run
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are computer program says answer number Haas I'm gonna answer
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50 and then go ahead and press Enter once I press enter
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50 is gonna be stored in the variable a
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says enter another number I'm can enter 32
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then I'm gonna press answer and that 32 is gonna be stored in the variable be
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and its can make our calculation and pronounce cream
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the summer those numbers is 82 50
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plus 32 is indeed 82 sir member what we did
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is basically this we made three variables that were gon be
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using later on the first thing he said is just basically a prompt
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answer a number then we entered 50
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its toward fifty in the variable a using c&
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again CNN is a way that the user can give information to the computer program
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said the other way around so now a is equal to 50
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you gave us another prompt and we typed in 32
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now be is equal to 32 sonar to calculate the sum we took the some variable
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and said equal to the some a fifty
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post 32 some now some
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holds the value I've 82 or 83 whatever i text and I can remember
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and then all we did is we printed a row on the screen and again
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we could've row three different statements for this one Cl
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for this 1c out for this 1c after this
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by in order to save us some time we can actually use this operator here
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and pray everything out on one line so that is why our program ran the weighted
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again
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it's a go ahead and run it one more time answer number 44
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and 76 to enter the summer those numbers is 120
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pretty cool are so that's how you build a basic calculator in C pas plus
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using variables and CL
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so now that you got that done on we can begin moving on to the next topic which
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is
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I don't know but trust me it's going to be amazing so
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arm you study this and want to understand the basics variables
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and CN you're ready to move on to next video so for now
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think ass rushing to you subscribe to now see in the next door