--- title: Intro to values and types in C# slug: intro-to-values-and-types-in-c published_at: 2020-09-10 17:15:02 +0000 updated_at: 2026-03-04 20:14:46 +0000 summary: description: tags: [dotnet, c#, .net, learn to code, beginner] views: 54 author: CJ Avilla url: https://www.cjav.dev/videos/intro-to-values-and-types-in-c youtube_url: https://www.youtube.com/watch?v=d9QY7-3QQHg youtube_id: d9QY7-3QQHg embed_url: https://www.youtube.com/embed/d9QY7-3QQHg thumbnail_url: https://i.ytimg.com/vi/d9QY7-3QQHg/hqdefault.jpg type: video --- # Intro to values and types in C# *Published: September 10, 2020* *Views: 54* ## Watch [Watch on YouTube](https://www.youtube.com/watch?v=d9QY7-3QQHg) [![Intro to values and types in C#](https://i.ytimg.com/vi/d9QY7-3QQHg/hqdefault.jpg)](https://www.youtube.com/watch?v=d9QY7-3QQHg) ## Description ## Transcript a computer program is a list of instructions that can be followed by a computer to perform a specific task most programs work by taking some input data processing that and creating some output data understanding the values and types will form a foundation on top of which we can build up concepts that will allow us to write our own programs so values are the actual underlying raw numbers and text our program manipulates tony stark the number 43 and false are all examples of values sometimes we'll say that when we literally write the number four and then the number three next to each other to form the number 43 that we're writing the literal 43 same with tony stark if we write the quotes then the letters t o n y etc into our code we'd say that we're using the string literal tony stark sometimes we might say that this is hard coded meaning that when the program runs the literal value isn't going to change literal values are used a lot when you're first starting out but eventually data will likely come from a database or some user input every value belongs to exactly one data type the kinds of values that can be represented and manipulated in a programming language are known as types all of these literals that we've written so far can be categorized as a specific type we see string number and boolean those are the types for tony stark 43 and false most languages use a very similar list of super simple types like a collection of characters as a string of text a list of digits with or without a decimal point as a number and then some type for representing true and false some programming languages will have more types that they have built in other programming languages will have a very small set of these primitive built-in types that you are to use to build up to more complex types when a program needs to use a value again in the future it assigns that value or sort of like stores that value in a variable variables have names and they allow us to use those names in our programs to refer back to the values we'll talk more about variables later here we're assigning the value 7 a name age we're also assigning the string grayson to the variable name first name if we wanted to print out the value 7 using the variable age we might call some print function and pass in the variable name or the literal number 7 and we'll take a look at how to print out the number or the string or whatever value it is in different programming languages there's really two different kinds of types there are built-in types and then there are user defined types built-in types are the types that come with the language this is the batteries included stuff like numbers and strings and dates and arrays and object types user-defined data types are defined in terms of built-in data types and other user-defined data types here we're defining a student type or we have defined a user-defined type called a student type which is composed of or made up of other built-in types the number for the the age and the string for the first name we might also create a car type which takes in a make and a model both of which might also be user defined types typically a programming language does not let the programmer extend or redefine those built-in types next a type can either be mutable or immutable these primitive types like 7 and true are immutable meaning they cannot change you can change the value of the variable meaning you can change what the name of that variable is referencing by pointing the variable at a different value however there's no way to change what the number seven means when we talk about the number seven there's no way we can like modify the number seven to be the number eight or the number six we wouldn't want to change what the number seven means similarly with true we wouldn't want to change what it means for something to be true a mutable object can change all right i'm using reply today i fired up a brand new repel using the c sharp programming language on the right hand side we have our terminal output in the middle pane we have our editor we see that we're working in main.cs which is uh the file that we're going to be working in the boilerplate that was added here had a the using statement for importing the system library we have a class definition with a public static void main function which will execute and here's the code that we're actually going to write so we're going to modify line 5 here and this will console.writeline is how you can print stuff in c so we're going to print this literal string literal hello world if we run this code by clicking the run button here and this will execute our c sharp code and print to the console and we see that it is printing out hello world so if we remove this and type in you know the number 43 from our example earlier we'll see that the number 43 is printed again this is the literal value 43 this is the the literal number uh 43 and the one other thing i want to talk about is commenting so generally with commenting you're going to add comments to your code to describe what the code does to remem to remind your future self of how something is working and so in c sharp there's a couple different ways to add comments but one way is by adding the slash slash to some part of the line that will comment out the rest of the line this says this tells c sharp that it should not execute the code that is commented out or the code that comes after these these two slashes so i'm going to use a commenting out to keep track of stuff that we've already run so that you can reference it later but this is just just to show you that when you comment code out in fact let's comment both of these lines out and click run you'll see that nothing is printed printed to the console because when code is commented out it is not executed all right let's talk about printing out tony stark so if we replace 43 here with tony stark and attempt to run our code right this is the string the name tony stark if we run our code we get an error so the error here on the right tells us that the file name that the error occurred on so this is main.cs and then there's two numbers here 6 and 27 the very first number number six tells us what line in this file the error is on so we're on line six that's that error is on line six and then 27 tells us what character it's on so s here is the 27th character on the sixth line in main.cs it says unexpected symbol stark so this is thinking that maybe it should have a closing parenthesis here or a comma and likely that tony and stark are different variables or constants that are referring back to something else but not a string literal so when when we're writing our c sharp code we need to tell c sharp where the string meaning like where the collection of characters begins and where it ends and we do that with double quotes so we add a double quote at the beginning to say where the string is starting and a double quote at the end to say where the string is stopping or where it ends so if we run this we'll see that it does not fail anymore and we get the output tony stark super cool let's keep going so if we again go back here and we add you know 43 plus 10 now we are adding an expression so we're not adding just a literal value 43 we're adding an expression so we have 43 followed by the plus operator followed by the number 10 so what's happening here is this expression everything that's highlighted 43 the plus and the 10 that expression will be evaluated so we're going to find what is the arithmetic or arithmetic result of adding 43 and 10 and then we will replace this entire expression with the value 53 so that will kind of the as the code is running it will say take 43 and add it to 10 whatever the result of that is use that and replace this expression with that value so we it would be replaced by 53 then that 53 value is passed to the rightline method on the console object and then it's going to be printed to the console so if we run this we get back 53. all right what happens if we add two strings together so let's uh let's copy that and see what happens if we try to add tony plus stark so these are two string literals tony is one string and stark is another string we know the string literals because we've written them directly into the code here they start with a double quotes they end with double quotes and in between these two string literals we're using again the plus operator but it doesn't really make sense to add the string like the word tony to the word stark right in in any like arithmetic terms you don't add tony and stark and get back 153 right so instead what happens is when we're using strings with the plus operator we're going to concatenate the two strings so concatenation means linking things together in a series so here we're going to link together the string of characters tony and the string of characters stark and print those out so we'll get back tony stark something that you might notice immediately is that there's no space between the first name tony and the last name stark here a couple alternatives to fixing this one might be that we go into the word tony we add a space so that when it's when it's run we have tony space stark okay another alternative might be to concatenate tony and stark with a third string in the middle that just has an empty space so if we run that we'll see that we get back the same thing so tony and stark right cool so this is concatenation string concatenation super helpful for when you're when you're building up output that you want to print to the console let's also print out a boolean value so false false is one of our boolean values that we talked about and we get back false in the terminal one thing that can be really helpful when you're working with values is to know what the type of the value is so if we have the word tony as a string we can call the method get type on that string to get the type of the value so we get back system.string so tony when we're using the double quotes around tony the type of that is system.string similarly if we replaced tony with the number 43 we should get back the type the data type for that number literal 43. system.int32 that's great what if instead of using just the number 43 if 43 had some dis some decimal value so 43.123 if we get the type of that we'll see that it's a system.double if you have integer values which don't have a decimal place value those integer values are treated a little bit differently than we would treat a floating point number that has a you know the the decimal point and some value after and this is this has to do with the way that numbers are stored in memory as binary so something to keep in mind and that these two different types are that these two types are different 43 without a decimal place 43 with a decimal place those are two different things all right that's really the basics for values and types in c sharp you --- [Back to all videos](https://www.cjav.dev/videos) --- ## Hey Agent, thanks for visiting! 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