So, in this module, we're going to talk about basic data types, and we're going to start with Pointers, which maybe is an unusual place to start the discussion of data types, but that's where we're starting, because people who are taking these courses generally already know something about programming. So, let's go straight to these Pointers and talk about them. A pointer is an address to some data in memory. So, I got to say every variable is located in memory somewhere, in some data staying in memory somewhere. Also, functions and so on, they're all in memory somewhere. A pointer is the address of that in memory. Tips give virtual address but that doesn't matter to us too much right now. So, with Pointers, there are two main operators that are associated with Pointers. The ampersand operator right there, that returns the address of the variable or the function, whatever the name is referring to, and the star operator which dereferencing, does the opposite of the ampersand. It returns the data at the address. So, the ampersand operator, if you put that in front of a variable, the name of a variable, that will return you the address of that variable. The star operator goes the other way. If you put that in front of a Pointer, to some address, put that in front of an address, it will return you the data at that address. So, it's important to understand this ampersand operator and the star operator are opposites of one another. So, I'll give you an example, take the look at this code, little piece of code, we define our variable X is an integer, it's equal to one. Then, Y is an integer and it's not initialized, so that would mean it would be by default initialized to zero. Then, a var IP. So, IP is not declared to be an int, it's a star int. Right? So, that means IP is actually a Pointer since there's a star operator in front of the int, IP is declared to be a Pointer to an integer. So, IP is the Pointer, but it is not an actual integer, is a Pointer to an integer. So then, if we go on, IP equals ampersand X. X is actually an integer. Right? Integer whose value is one. So, there is a number one sitting in memory somewhere, and X is a reference to it, the name of that. Ampersand X is the address in memory where I can find that value one. So, IP is now equal to that address. So, whatever the address of that one, is rather, of X, whatever that address is, IP is the Pointer to that address, it is the address. Then, in the next line, I say Y equals star IP. So, remember that in this little example, IP is actually a Pointer and the data at that address that IP is pointing to, is the value one. Now, star IP, star does dereferencing. Star says, star returns the value, the data at that address. So, Y is now equal to the data at the address that IP is pointing to. Now, if you remember for line for IP is pointed to what X is pointing to. Right? So, IP is pointing to the value one, that data in memory. So Y, if Y is equal to star IP, Y is equal to one. So, this now sets Y equal to one. It is just a little example here, just trying to show how the ampersand and the star operators work opposite to one another. So, these are Pointers, and Pointers exist. These Pointers are basically, if you now see same type of implementation. Now, there's another function called New. It's another way to create a variable. New, instead of returning a variable, it returns a Pointer to the variable. So, the new function creates a variable and it returns a Pointer to that variable. So, this is unlike, if we're just declaring a variable, right? That also creates a variable, but New explicitly returns a Pointer to a variable. So, the variable is initialized to zero by default with New. So, for instance here, if I say our Pointer equals new int, and then star Pointer equals three, right? Pointer was new int, new int returns me a Pointer to an integer, and that PTR is equal to that Pointer. Then, I can set the value of that integer by referring to star PTR, right? Because star PTR is the value that PTR is pointing to. If I say star PTR equals three, then the value three is placed at the address specified by PTR.
