Before you can use a variable you have to declare it first. The variable can be declared either implicitly using the 'var' keyword
or explicitly specifying a data type the variable should have.
In the code below:
The variable x is declared implicitly. Its data type wasn't explicitly specified, instead, in the place of the data type the keyword 'var' is used.
Because the data type isn't explicitly specified and every variable needs to have its data type,
the data type gets inferred from the value that is assigned to the variable.
The variable y is declared explicitly, which means its data type was specified before any value got assigned to the variable.