Introduction to Variables
In today's lesson, we will discuss variables in C programming.
Imagine a glass of water. When you want to drink water, you pour
it into the glass and then drink from it. You can think of a variable
as a glass of water. Just like a glass can hold water, variables can
hold values. Once you store a value in a variable, you can use
that value in your program.
In reality, variables are simply names that point to specific
memory locations. Thanks to the inventor of the C language, it is
easy for us to store values in memory by just using a name of our
choice. You don't need to worry about the exact memory location
where your value is stored. Your task is to provide the name, and
internally it will be associated with a memory location.
However, there is one important thing to note. You must declare
variables before using them in your program. Declaration means
announcing the properties of the variable to the compiler.
Properties of a variable refer to its size and name. Declaring a
variable is a simple task. It involves specifying the variable's
name and data type, which determines the amount of memory it
will occupy. In most cases, declaration and definition are done
simultaneously, but it can vary depending on the modifiers used
with the variables. Let's look at an example of declaring a
variable:
int var;
In this example, the variable name is "var" and its data type is
integer. By writing "int var", you are declaring the variable and
requesting the compiler to allocate memory for it. It is important
to remember to end the declaration statement with a semicolon,
as it separates one statement from another.
The amount of memory allocated for a variable depends on its
data type. In the case of an integer data type, it could occupy
either two or four bytes of memory, depending on the system you
are working on.
