So far we've looked at some numerical data types -- int and double -- but it's also possible to store text characters in variables. This is done using the character or "char" data type.

Here I've added a new char variable named "letter". Now let's say I want to set the value of "letter" to a lowercase 'a' -- there are two ways I could do this.

One way would be simply assigning letter the value "a" enclosed in single quotes, like so.

Another way would be by assigning our letter variable a numerical value.

Since we can only store numbers inside a computer's memory, each character is assigned a number.

Most computers use a code known as 'ASCII', which assigns each character values somewhere in the range from 0 to 255.

Here's a list of characters whose values are between 32 and 127. As mentioned earlier, there are more chars than this, but these are the ones you are most likely to use.

While you really don't need to memorize these, one thing that is useful to know is that the codes for lowercase letters are contiguous (one after the other without a gap). In other words the code for lowercase 'b' is one more than the code for lowercase 'a'. Similarly, uppercase letters are also grouped together, as well as the numbers 0 to 9. However, there *are* gaps between these groups, so don't expect a lowercase 'a' if you add 1 to an uppercase 'Z'. 

If we look at this list, we can see that the ASCII code for lowercase 'a' is the number 97.

Let's run the visualizer and see what happens.

Here we see that letter currently stores a lowercase a.

As expected, executing the next line does not change the value of our variable.

Before we finish here, let’s do one more thing with our example.

What do you think will happen when I add this line?

From previous videos, we know how expressions are evaluated. 

First, the right-hand side of this expression is evaluated. And then, that value will be assigned to the variable on the left hand side. But what do we get when we add 1 to a char?

When I press next to execute the statement, we see that letter changes to ‘b’. That’s because the code for b is one more than the code for a (so 98).

C programmers sometimes take advantage of the fact that the ASCII codes for letters come in order.