ESP - Week 2

Question 1

Arrays

Answer 1

Arrays are lists indexed from zero

Question 2

Arrays Syntax

Answer 2

int list[10]; - A list of 10 integers

Question 3

Records/Structs

Answer 3

Combines 3 integers into a single data structure

Question 4

Records/Structs Syntax

Answer 4

struct rgb {
int red;
int blue;
int green ;
};

struct rgb purple = {255,0,255}, p;

p = purple;
p.green=123;

Question 5

Strings

Answer 5

Strings are arrays of characters with a zero/null character at the end

Question 6

Strings Syntax

Answer 6

char name[] = “Hello”;

Question 7

What is a cast

Answer 7

int(ch) - Changes the type from char to int

Question 8

What is the final character in a string

Answer 8

A zero which is not printed

Question 9

String data type

Answer 9

String is also a datatype which is more flexible but takes more memory

Question 10

What is abstraction

Answer 10

A mechanism for hiding details we don’t need to see in an object

Question 11

Simple lcd commands

Answer 11

lcd. begin(16,2) - Tells library screen is 16x2
lcd. SetCursor(x,y) - Puts cursor at (x,y)
lcd. print(“text”) - Writes text on screen

lcd.setBacklight(x)

Question 12

What is the purpose of lcd.readButtons()

Answer 12

Returns bitstring with one bit for each button being 1 for on and 0 for off

Question 13

Bytes for colour

Answer 13

0 - R
1 - B
2 - G

Question 14

Generating new characters

Answer 14

byte a[] = {4,14,31,etc.};

lcd. createChar(UPARROW, a);
lcd. write(UPARROW)

Question 15

How to return number of seconds since powerup

Answer 15

unsigned long millis();

Question 16

Arithmetic with floats

Answer 16

Int/Int = Int
Float/Int = Float
(float)Int/Int = Float