For and While Loops in C++ | Beginner C++ Tutorial

what's up you guys welcome back to the channel and today's video is going to be a continuation in our c plus tutorial series in this video i'm going to show you a basic introduction to four and while loops in c plus using microsoft visual studio [Music] all right so let's jump right into it a for loop and a while loop by far in programming the two most common types of loops essentially a while loop is going to run indefinitely until a certain condition is met a for loop is going to run at a predetermined number of times and these are two different ways to create recurring code that you want to have occur a certain number of times a lot of times while loops are used in like games waiting for certain events to trigger actions and a for loop is something like populating an array or a list where you know the overall size of it so both of them are valid in most applications of programming a lot of people just end up with one that they prefer more than the other and in c plus it's just like any other programming language it's no exception almost any time you use a while loop there's a way of setting it up with a for loop but they definitely have advantages and a few um little differences between each other so let's just get right into um writing examples of both okay so let's start with the while loop and getting started here i'm going to start by creating a variable that i'll call in in index and i'm going to just call it 1 initially so in indexes if this is if you're familiar with programming concepts this might be something you've heard before it's essentially where you're at in a list or a sequence or in a book it quite literally tells you like uh it's a list of different events um like what page you can find different concepts on so it's a good thing to know index is typically where you are in a list uh how far you've gone in a for loop anything like that that's what an index variable typically is and then i'm gonna print out just on the screen that we're doing this stuff for the while loop because as you'll see the while loop is going to run a whole bunch of times and then after that we're going to put the for loop to kind of show both of them working so we're just going to put on the terminal window that this is the while loop we're working on now to actually start a while loop and call it you put while like this and then in parentheses you just put your condition for what you want it to run until and for this we're just going to say while index is less than or equal to 10. it's a really simple concept a really easy while loop to think about and basically the first thing you need to do when you create a while loop is add the condition that could exit you from that while loop programming it's not valid to have an infinite loop which is a while loop that you can never escape so basically first thing you want to think about is how do i escape this loop because an infinite loop will crash your computer or worse in old hardware that's the kind of thing that could create like a fuse to blow so i'm going to use the c plus shortcut for adding one to a value which is a double plus and so inside this while loop i'm just going to say add one to the index value now this while loop if i were to run just this program it would run but what you'd have is really useless because we're not displaying the result anywhere but what's going to happen is this code's going to boot up it's going to see that index is 1 which is less than or equal to 10 so then it enters this while loop and it's going to say okay index is 1 and then add 1 to it and go to 2 and then it's going to see while index is less than or equal to 10 well 2 is still less than equal to 10 so it'll run again 3 4 5 6 7 8 9 in that loop and then 10 again so to show what's going on here let's actually print the index that we're currently on onto the screen and so the code is going to run so fast that if we weren't using that index for any real thing you'd never know this had run 10 times but if i print the index onto the terminal window if i run this now you're gonna see on the window here you go while loop one two three four five six seven eight nine ten so that code ran 10 times it did it so fast that we couldn't process that code was happening ten times but our loop executed 10 times so these are really useful when you don't necessarily know the event that's going to exit because right here you're saying well we told it to run exactly 10 times why wouldn't you use a for loop for that and you're right you don't need this to be a while loop we can make the exact same loop in a for loop and we will in just a second um but i wanted to show the basic format of how you set up a while loop a lot of the times you'd say while grade is less than 90 or something and you're just looking for a student who has an a in your class so you'd say while grade is less than 90 index go through the this index of my class and look at the different students and their grades and if they are less than 90 then just keep going so i want to keep looking until i find a student with an a something like that now let's go ahead and i'm going to copy these uh this kind of overall just so i can change it to for loop now and let's take a look at what we do instead of a while loop to set up a for loop okay and for this it's still you know you start with the word four instead of while that's probably the most obvious part of the formatting but then this next part is you give it three arguments you give it uh first thing you want to give it the indexer value index or variable and for this we're going to create an index that's just called i instead of index and i'm going to set it equal to an initial value of 1. then we say the conditions we want to run the for loop on so we'll say i is less than or equal to 10 okay and this is always going to be essentially what you would put inside the while loop condition this is saying how many times to run it so while i is less than or equal to 10 we are going to have the i index or variable operate in this for loop and then the third argument you give a for loop is what to do to your index or variable um and it's going to be in this case add one to it every time so if you want the index to like um multiply by two every time instead you could do uh like times equals two so basically this would go one two four eight sixteen there's all sorts of different things you can do with this but basically we're just going to add one to do the exact same thing and then instead of this index plus plus down here we can just get rid of that line because now we have the uh index plus plus in the command loop for the for loop and then we will just c out console out the uh result of i now and so when i load this up you'll still see that one through ten for the while loop but you'll what you'll also see oop looks like i paused it there we go what you'll also see is 1 through 10 for the for loop right underneath it so you have while loop one two three four five six seven eight nine ten for loop one two three four five six seven eight nine ten okay so obviously what they're outputting right now is exactly the same because i was showing you that you can use these two loops for a lot of similar concepts it's just up to you the designer the programmer to determine which way is going to be the right way for your application but let's take a look at let's say it's not as generic as just iterating through and displaying the index let's say we had an array of values so integer array of values with these square brackets and then we're going to put the actual values in curly brackets and let's just give it some values 1 2 45 63 23 7 6 5 8 9 78 105 okay so if we were to say now for the same loop that we just set up instead of just showing me i go ahead and show me the index values at i so um if you're not familiar with this indexer which i was talking about a little bit earlier in the in the program in the video each value inside of this array inside of this list has what's called an index value that tells you where in the list it is so i'm going to go ahead and run this and you can see instead of 1 2 3 4 5 6 7 8 9 10 we're getting all of these values 2 45 63 23 which if you look just below the console down here 2 45 63 23 pretty cool all the way through 78 the reason it started at 2 and stopped at 78 is because lists start they don't start from one in terms of index everything in programming across pretty much every programming language starts from an index of zero so this one is actually at i equals zero which means this is one two three four 5 6 7 8 9 and the 78 is 10. so if we wanted that 1 that first character to show up we just say i's initial value is equal to 0. now if i run this we'll get the same stopping at 78 but now we're gonna start from one which is great and if you wanted that 105 you would just change this to 11 and then you'd get everything in the whole list so that's just a basic example of how to use for loops how to use while loops in c plus plus but hopefully uh you found that informative if you have any questions on what you saw in this video or want to let me know what you want to see next on the channel be sure to let me know in the comments below um be sure to leave a like on the video subscribe to the channel all the support helps out a ton and as always thanks for watching and good luck with your projects thanks bye