Throughout this lesson, we’ve discussed the different ways we can manipulate a variable; however, what do we do with a variable that should never change its value?
For example, the year we were born will always stay the same. There’s no way we can change that information. A value like this in our code should be unchangeable.
To declare a variable with a value that cannot be manipulated, we need to use the final keyword. To use the final keyword, prepend final to a variable declaration like so:
When we declare a variable using final, the value cannot be changed; any attempts at doing so will cause an error to occur:
error: cannot assign a value to final variable yearBornInstructions
Create an unchangeable double variable called pi and set its value to 3.14.
Print the value of pi.
On a new line, try to change the value of pi.
What happens when the program is run?