User Input - C++ Tutorial For Beginners #6

Key Takeaways

it's not a game it's a [Music] r what is going on guys welcome back to the C++ tutorial series on nural 9 today's video we're going to talk about user input so let us get right into it all right so up until now our programs were pretty static we didn't have any user interaction we didn't have any uh information from outside of the program code everything we did was hardcoded every value that we chose uh was hardcoded and when we wanted to change something we had to change the code and recompile it and we're going to change this in today's video by introducing user input by by learning how to process user input and you already know about the function stdc out which takes some text and puts it out onto the screen uh but there's also the function called cin so SCD C in and it's the opposite thing it gets something from the console and gets it into the program code so to say um and let's say we just put out something like please please enter your name and we're not going to do an end line here because we want the user to continue to put the text into the same line um now what we can do is we can call the cin function but since this function is getting something from the console window from the user and putting it into this into the script uh not script sorry into the program uh this function is called C in and also we need to use the arrows in the opposite direction so in this case we don't say see out and then we feed something into it we we say C in and extract something out of it so in this case we can put this into a variable and let's create this variable by saying SD string name and then we say stdc in the result shall be saved in name and after that we can go ahead and say your name is name like that so when we have this we can go ahead press F6 uh enter the name let's say neural 9 and you can see your name is neural 9 in this case uh so this is how you process user input you just say C in and whatever you get out of cin by pressing enter in the end uh you save into the variable that you define um now you can also do this with other data types so if you now pass 10 it's going to be saved in a string so it's going to be not 10 as a as a numerical value but 10 like this uh as a string just a text 10 but if I change this for example to let's say in h and we say please enter your H and we want to see in the H and then you say your H is H uh this is now an integer so whatever we put into this uh program is going to be considered an integer we don't need to typ cast it it's going to be typ casted automatically the cin function returns or or what we whatever we extract out of the cin function uh will be the data type that we need in this case integer of course um I'm not sure if this is going to work with all classes and objects and data types but it works for INT it works for float it works for Strings and so on so for the primitive data types it seems to work and we can can look at it enter your age 10 your age is 10 and to see that this is actually an integer and not uh just a string you can go ahead and add 20 here to it just to see what happens and when we now enter 10 we get 30 and since we can Calculate 10 + 20 we know that H is in fact an integer as we already stated so this is how you process user input in C++ by the way for those of you who are wondering what I'm using to compile the program code all the time I'm using an extension here in Visual Studio code called CC plus plus compile run it is by Daniel pinto8 zz6 a very basic extension you just install it and then you can press F6 to compile the code and run it and you can press F7 to run it with some additional parameter for those of you who are wondering what I'm using to uh compile all the all the program code here by just clicking F6 all right so with the knowledge we now have we should be able to easily Implement a basic addition calculator with uh the numbers put in by the user so let's say we have something like int and one and two then we say see out actually by the way for those of you who are wondering you can also go ahead and say using STD um see out if you just want to use use STD C out and not import the whole namespace STD so if you want to do that you can do that with C out we can do that with C in and we can do that with endline uh I'm not claiming that this is in any way best practice or something but since we're just learning we can use it like that uh usually I think it's best practice to just say STD all the time so to specify it uh separately or individually every time um but since we're just learning here it doesn't matter too much if we're using best practices uh however we can now go ahead and just say C out and we can say please enter the first number like that and we're not going to use an end line here and we're going to do the same thing for the second number and in between we're going to say CN N1 and C in and two and in the end what we're going to do is we're going to say c out sum is or let's let's use an English sentence here the sum is N1 + N2 end line and if we compile and run this you can see we can enter a number here let's say 8 and 19 and we get 27 as a sum so that's how you uh can build a basic addition uh Dynamic Addition calculator in C++ by using user input and then a basic arithmetic operation now one more little thing that we can do with the cin function here especially when we're learning C++ is we can just wait for user input before we terminate the program so let's say we have something like hello world like in the first video where we did some actual code hello world uh the problem is when we go ahead and compile this here um and run it of course uh oh yeah we need Tod again we just go ahead and compile this and run run this it's going to work but as you can see the script uh not the script sorry the program terminated immediately and if we go ahead and uh go to the desktop here where this is compiled and we run it you can see that it opens up down down in the Tas but you can see it opens up for a second and then it's gone again because uh it's already terminated you just print hello world and that's it and you're gone if you want to wait uh before you terminate for a user input what you can do is you can say STD cn. get this essentially just waits for some user input before uh it proceeds with the code and since it's not proceeding since it's not done with everything yet that is coded inside of this program it's going to wait and the window is not going to disappear before you click enter so we're going to compile this here and when we do this oh of course we need a semicolon here when we do this you can see that it says hello world but it's it's not terminating it's still running when I press enter it's done and we can see that when we go ahead and run this executable file here we can see Hello World actually waiting for us for more input and I can put in some stuff here and it's still not terminating but when I click enter it's going to terminate and this is something that we can use in order to pause and to wait for the user to click enter before we actually terminate the script so that's it for this video hope you enjoyed and hope you learn something if so let me know by hitting the like button and leaving a comment in the comment section down below and of course don't forget to subscribe to Channel and click the notification Bell to not miss a single future video other than that thank you very much for watching see you in the next video and bye [Music]