2 + 3. Anatomy of a program

Question 1

when we run a program we are running

Answer 1

a) an object file
b) a machine language file

-computers understand machine language, and object files are in machine language

Question 2

object file

Answer 2

file containing object code

Question 3

use of xcode

Answer 3

to type in + edit your program files

Question 4

terminal utility

Answer 4

gives UNIX interface, used to enter UNIX commands to iMac

Question 5

terminal commands

Answer 5

cd: change directory
ls: show programs in folder
make: compiles program

Question 6

when compiling program

Answer 6

don’t type .cpp, just write the file name

Question 7

troubleshooting: ‘program’ is up to date

Answer 7

probably forgot to save edited program

Question 8

troubleshooting: no rule to make target ‘program’

Answer 8

mistyped filename or file not in current directory

Question 9

troubleshooting: use of undeclared identifier

Answer 9

syntax error, didnt declare a variable

Question 10

Use of // or /* */

Answer 10

a comment (ignored)

Question 11

include

Answer 11

allows program to use built-in facilities for input and output (IO)

Question 12

int main () {}

Answer 12

a function that returns an integer (int), function is called main

Question 13

return 0

Answer 13

main returns the integer 0

Question 14

{ }

Answer 14

used to define functions/processes

Question 15

variables

Answer 15

places which store values

Question 16

valid variable names

Answer 16

start w/ letter or underscore

rest is letters, digits, or underscore

Question 17

notes on using variables

Answer 17

• case sensitive eg. rate vs Rate vs RATE

- don’t use reserved keywords eg. int, for, while

Question 18

data type

Answer 18

what kind of thing you want to store in a variable

Question 19

Data types

Answer 19

• int
• double
• bool
• char
• string

Question 20

int

Answer 20

integers

Question 21

double

Answer 21

decimal number

Question 22

bool

Answer 22

true/false values

Question 23

char

Answer 23

used to hold a letter/digit or other symbol eg. “a” “&” or “ “ (a space)

Question 24

string

Answer 24

for sequences of characters eg “hello”

Question 25

note on double: float

Answer 25

can be used for smaller less precise numbers

Question 26

note on string

Answer 26

include

data type not built in, must include string library at top

Question 27

variable declaration

Answer 27

variables + data types must be declared before use

Question 28

giving variables values

Answer 28

a) reading eg. cin&raquo_space; x;
b) assignment eg. sum = 0; name = “Mary”;

always give variables an initial value before use

Question 29

=

Answer 29

the assignment operator

Question 30

iostream

Answer 30

contains definitions for cout and cin

Question 31

cout and cin arrow directions

Answer 31

cout «

cin&raquo_space;

Question 32

/

Answer 32

divides

eg. 10/3 = 3 (for int)

Question 33

%

Answer 33

remainder

eg. 10%3 is 1

Question 34

integer division

Answer 34

only if both operands are integers that division is integer division

Question 35

cmath library common commands

Answer 35

cos/sin/tan
exp
log
pow
sqrt
fabs

Question 36

assigning int to a decimal value

Answer 36

by assigning a decimal value to an int variable, you effectively drop the decimals

eg. 
int i;
double x = 3.1415;
i = x;
i will equal 3