7. Programming (3)

Question 1

Is button bounce an issue for a light switch?

Answer 1

No, the light will just light up or not and bounce won’t effect the overall result.

Question 2

When would button bounce be an issue?

Answer 2

When the button is used for setting a program on a system. At each press the machine toggles to the next available program. Button bounce will be an issue because we don’t want the system advancing a random number of programs each time the button is pressed.

Question 3

What does a rounded rectangle mean?

Answer 3

Beginning or end of a process

Question 4

What does a rectangle mean?

Answer 4

A generic program step

Question 5

What does a parallelogram represent?

Answer 5

An input/output

Question 6

What does a diamond mean?

Answer 6

A decision. This will have two arrows coming from it: one for yes and one for no.

Question 7

What does a rectangle with double vertical edges represent?

Answer 7

Subroutines

Question 8

What do arrows show?

Answer 8

Direction of flow

Question 9

What are the steps towards writing a program?

Answer 9

1. Establish/write down the requirements
2. Use a flowchart to show how the requirements can be met
3. Then you are ready to start writing code

Question 10

What is an initialization block?

Answer 10

The beginning of the flow chart: start -> set initial states

Question 11

What is the main loop?

Answer 11

The main loop is where all of the main requirements are met

Question 12

How is a decision step written in C?

Answer 12

Using the if statement:
if(condition)
{ 
// things to do if true
}
else
{
// things to do if false
} 
Where the 'else' part is optional.

Question 13

What does == do?

Answer 13

tests for equality

Question 14

what does != do?

Answer 14

tests for inequality

Question 15

what does > do?

Answer 15

tests for greater than

Question 16

what does >= do?

Answer 16

tests for greater than or equal to

Question 17

what does

Answer 17

tests for less than

Question 18

what does

Answer 18

tests for less than or equal to

Question 19

what does if (buttonstate) do?

Answer 19

true if buttonstate is non-zero, fales if butonstate is zero

Question 20

What is the scope of a variable in a C program>

Answer 20

Scope describes where the variable can be seen and cannot be seen.

Question 21

What is file scope?

Answer 21

A variable defined at the top of the file has file scope, and can be seen and used by any function in the program. For a single file program such as we will be writing, file scope == global scope.

Question 22

What is a variable with global scope called?

Answer 22

A global variable

Question 23

What is function scope?

Answer 23

A variable defined within a function can only be seen within that function. Another function cannot make use of this variable. Generally a good thing, can sometimes be a nuisance.