chapter 6

Question 1

what is the main thing computers do with data?

Answer 1

For all their complexity, the main business of computers is to move data from one place to another. Take a number — the balance in a person’s bank account. Move this number from the computer’s memory to the computer’s processing unit. Add a few dollars to the balance and then move it back to the computer’s memory. The movement of data

Question 2

what is a variable and what happens when you change the variable in your code?

Answer 2

A variable is a placeholder. You can stick a number like 5.95 into a variable. After you’ve placed a number in the variable, you can change your mind and put a different number, like 30.95, into the variable. (That’s what varies in a variable.) Of course, when you put a new number in a variable, the old number is no longer there. If you didn’t save the old number somewhere else, the old number is gone.

Question 3

what is stored in a variable & what kinds of variables can be stored in a variable?

Answer 3

The thing stored in a variable is called a value. A variable’s value can change during the run of a program. The value stored in a variable isn’t necessarily a number. (You can, for example, create a variable that always stores a letter.)

Question 4

what is a variable type?

Answer 4

the kind of value stored in a variable is a variable type.

Question 5

what is a variable name and how is it different from a variable?

Answer 5

There’s a subtle, almost unnoticeable difference between a variable and a variable’s name. Even in formal writing, I often use the word variable when I mean variable name. Strictly speaking, amount is the variable name, and all the memory storage associated with amount (including the value and type of amount) is the variable itself.

Question 6

what else is a variable name besides the name of the variable itself?

Answer 6

a variable name is also an identifer– a name that you can make up in your own code.

Question 7

what is an assignment statement ?

Answer 7

The statements with equal signs are called assignment statements. In an assignment statement, you assign a value to something. In many cases, this something is a variable.