Comp 2160 Final

Front 1

"Let the data structure the program" def

Back 1

Replace complicated code with an appropriate data structure. Before writing code, understand the input, output, and what the best data structure for the data is.

Front 2

Unix line ending

Back 2

"\n"

Front 3

DOS line ending

Back 3

"\r\n"

Front 4

when we create an object the system will allocate space on the

Back 4

heap

Front 5

memory leak example

Back 5

a = malloc(...)

a = NULL;

Front 6

How would you test a sort?

Back 6

systematically test the edge cases:

- list of length 0

- list of length 1

- n sorted #s

- n reverse sorted #s

- n identical #s

- n random #s

Front 7

Testing: the general case is ______ _____

Back 7

not enough

Front 8

Why should an ADT be kept in a separate file?

Back 8

for re-use

Front 9

symbol table def

Back 9

stores information about variables, functions, objects, classes, etc.

Front 10

our header file contains our

Back 10

public interface

Front 11

<> tells preprocessor to look in:

Back 11

system locations

Front 12

"" tells preprocessor to look in:

Back 12

current directory

Front 13

header guard example:

Back 13

util.h:

#ifndef _UTIL_H

#define _UTIL_H

...

#endif

Front 14

#pragma use

Back 14

put at the top of a file to only be included once in compilation

Front 15

what if 2 separate files happen to use the same identifier for a fcn?

Back 15

it will compile and create an object file, but the linker will give a multiply defined error

Front 16

static keyword

Back 16

private. i.e local use only

Front 17

every variable has a ____ and a ______ _____

Back 17

type, storage class

Front 18

storage class def

Back 18

determines which functions "know" what vars exist and how long a var "lives" in a pgm

Front 19

5 storage classes

Back 19

- auto

- external (NOT extern)

- static

- register

- volatile

Front 20

all vars declared in a routine are ____ unless declared otherwise

Back 20

auto

Front 21

an automatic var has a ______ scope, therefore it's stored in the _____

Back 21

local, RTS

Front 22

external def

Back 22

an variable declared outside a routine

Front 23

an external variable is stored in

Back 23

DATA section

Front 24

keyword for external

Back 24

no keyword

Front 25

get an external static variable by

Back 25

declaring a static variable outside any function

Front 26

external static variable can only be used by ____ in the same ______

Back 26

functions, file

Front 27

global variables def

Back 27

anything accessible between files

Front 28

why are global variables bad?

Back 28

breaking the contract defined through the header. Results in unknown changes

Front 29

always make external variables _____

Back 29

static (private)

Front 30

how to separate a program into multiple files

Back 30

- ADTs get their own files

- define subsystems and group those

- if they go together in a class, the belong in a module

Front 31

coupling def

Back 31

reliance on other modules

Front 32

higher coupling = more likely to:

Back 32

be affected by changes

Front 33

in general, _____ coupling is better

Back 33

lower

Front 34

cohesion def

Back 34

the degree to which a function adheres to 1 task

Front 35

low cohesion =

Back 35

doing many independent tasks, resulting in side effects caller wasn't aware of

Front 36

how to control coupling

Back 36

ADTs

Front 37

int a[10];

int *ptr1;

ptr1 = a;

*ptr1 gives me:

Back 37

contents of a[0]

Front 38

char *str;

str = "Hello World";

str points to:

Back 38

the first character in the string

Front 39

ptr1 = &a[0] then how to get a[1]?

Back 39

*(ptr1 + 1)

Front 40

C increments or decrements a ptr in:

Back 40

multiples of the object size

Front 41

Why is looping through an array with address arithmetic more efficient?

Back 41

- Subscripting requires a multiplication and addition

- pointers directly store the address of the obj, no math needed to get to the contents

Front 42

int a[10];

T/F: a and &a[0] are the same address

Back 42

T

Front 43

malloc allocates any # of ________ _______ ______

Back 43

contiguous memory locations

Front 44

contiguous memory location def

Back 44

blocks of memory in sequence.

e.g. an array

Front 45

i = malloc(10*sizeof(int));

T/F: we can do: i[0], i[1], i[2], etc.

Back 45

T

Front 46

T/F: C memory mgmt routines (memcpy, memcmp, memset) have a '\0' check

Back 46

F

Front 47

optimization is about:

Back 47

finding ways to do less work, not to make current work faster

Front 48

hotspot in code def

Back 48

called the most or runs the longest

Front 49

3 ways to optimize for time

Back 49

1. pre-compute and store info in a table or variable. e.g. constants like pi, length of a string or array, etc.

2. find a better data structure

3. caching

Front 50

sparse data def

Back 50

a high percentage of the variable's cells are empty

Front 51

2 ways to optimize for space

Back 51

1. use a data structure that uses only the space it needs

2. make the most out of the space we have. e.g. boolean only needs 1 bit

Front 52

members of a union all share:

Back 52

the same memory

Front 53

variables inside a union are:

Back 53

mutually exclusive

Front 54

unions are useful for marking ________ objects

Back 54

polymorphic

Front 55

disadvantage for mark and sweep GC

Back 55

scans all memory twice, program freezes while GC is happening

Front 56

advantage of mark and sweep GC

Back 56

frees the programmer from manual memory management

Front 57

IDE stands for

Back 57

Integrated Development Environment

Front 58

static when applied to a external variables and functions

Back 58

limits the scope of the vairable or function to the source file containing its definition

Front 59

static when applied to a automatic variables

Back 59

causes the variable to remain in existence and retain its value between function calls

Front 60

What does DBC's contract guarantee us?

Back 60

that we always leave an object in a valid state

Front 61

Problem with goto

Back 61

our clean-up code gets separated from creation code

Front 62

defer block

Back 62

block that holds the cleanup code - put it directly under the creation code