Comp Sci Test 1

Front 1

What's the format descriptor for an integer?

Back 1

%d

Front 2

What's the format descriptor for a double?

Back 2

%lf

Front 3

What's the format descriptor for a character string?

Back 3

%s

Front 4

What does "\n" mean?

Back 4

Creates a carriage return or new line.

Front 5

What function reads from the keyboard/command line?

Back 5

scanf

Front 6

What is used to address variables, but not character strings?

Back 6

&

Front 7

How do you declare an input file?

Back 7

FILE *infile;

Front 8

Open files with:

Back 8

fopen

Front 9

Allow the computer to read a file with:

Back 9

"r"

Front 10

Allow the computer to write into an output file with:

Back 10

"w"

Front 11

Function that writes to an output file:

Back 11

fprintf

Front 12

Function that reads from a file:

Back 12

fscanf

Front 13

Function that closes a file:

Back 13

fclose

Front 14

What kind of loop repeats something a fixed number of times?

Back 14

for loop

Front 15

What variable type should you use as a counter?

Back 15

integer

Front 16

What kind of loops keeps repeating as long as a statement is true?

Back 16

while and do loops

Front 17

When do "while" loops check to see if the loop should be executed (again)?

Back 17

Before starting

Front 18

When do "do" loops check to see if it is executed (again)?

Back 18

After the first pass/ At the end

Front 19

What include header defines variable types?

Back 19

#include <stdio.h>

Front 20

Statement that only does something is a given statement is true.

Back 20

if statement

Front 21

Picks between two options depending on whether a given statement is true or false.

Back 21

if/else statement

Front 22

Chooses based on the first true expression the computer finds.

Back 22

if/else if/else statement

Front 23

Chooses between several options based on the value of an integer or character.

Back 23

switch statement

Front 24

Function that every code must have:

Back 24

main()

Front 25

How many values do functions return?

Back 25

one

Front 26

Functions take ________:

Back 26

arguments

Front 27

Functions have syntax defined by these type of statements:

Back 27

prototype

Front 28

These allow direct access to memory locations where variables are stored in 1's and 0's:

Back 28

pointers

Front 29

Address pointers via:

Back 29

&

Front 30

Give content to pointers via:

Back 30

*

Front 31

In function prototypes use these as arguments to pass pointers into functions:

Back 31

pointer-to-values

Front 32

Call with these as arguments when passing pointers to functions when calling the function:

Back 32

pointer-to-address

Front 33

In the function definition use these as arguments when passing pointers into functions:

Back 33

pointer-to-values

Front 34

What is an operating system?

Back 34

Software that supports computer basic functions. Manages hardware and software resources and common services for computer programs (i.e.memory processes). Allows you to speak the computers language.

Front 35

What are the main hardware parts of a computer? (There are six)

Back 35

Central Processing Unit (CPU), Northbridge/Southbridge, Memory, Hard drive/disk, Input devices, Graphics card

Front 36

What is a compiler?

Back 36

Translates human-readable code into low-level instructions for the CPU.

Front 37

Lists files in the directory

Back 37

ls

Front 38

Lists files in the directory with sizes shown

Back 38

ls -l

or

ls -al

Front 39

Renames the files

Back 39

mv

Front 40

Moves the files into a subdirectory

Back 40

mv file.cpp sub

Front 41

Define an integer variable i:

Back 41

int i;

Front 42

Define a floating point variable with value 3.14 which can't change:

Back 42

const double PI=3.14;

Front 43

Statement to read a double value from the command line into a variable named discount:

Back 43

scanf("%lf", &discount);

Front 44

Print double variable q in scientific or floating point notation, whatever's more compact:

Back 44

printf("%g", q);

Front 45

Using file pointer, input_file, open the file results.dat for read mode:

Back 45

input_file = fopen("results.dat", "r");

Front 46

Reads an integer from the program's command line:

Back 46

int i = atoi(argv[1]);

Front 47

Function pointer type that can point to sqrt() function in the C math library:

Back 47

double (*f)(double x)

Front 48

All C functions must contain:

Back 48

main()

Front 49

Correct operator to compare two numerical values:

Back 49

==

Front 50

How man times is a "do while" loop guaranteed to loop?

Back 50

1

Front 51

What is a parent distribution?

Back 51

Represents the probability of observing a particular value w/ infinite points (i.e. in a perfect world).

Front 52

What is a sample distribution?

Back 52

Experiments draw measurements at random from the parent distribution. Creates a histogram.

Front 53

Role of the Gaussian distribution in measurements?

Back 53

Measures of random processes, in the limit of many samples, often tend to produce a characteristic Gaussian/Normal distribution.

Front 54

What's the Central Limit Theorem?

Back 54

Sufficiently large numbers of randomly distributed measurements will always approach a Gaussian distribution.

Front 55

What's a systematical uncertainty?

Back 55

Features of the measurement device or technique that shift the measured result to the true value.

Front 56

What's a statistical/random uncertainty?

Back 56

Features of the measurement device or technique that shift the measured result by a different amount in each attempt (random).

Front 57

What's a CPU do?

Back 57

Does the actual computer work. (i.e. the brain)

Front 58

What's a Northbridge/Southbridge?

Back 58

Middlemen that handle fast and slow input/output and inter-component communications.

Front 59

What's Memory?

Back 59

Temporary storage of data needed rapidly when running programs.

Front 60

What's a Hard drive/disk?

Back 60

Permanent, long-term storage of data.

Front 61

What's Input:

Back 61

Enables interaction w/ users.

Front 62

What's a graphics card?

Back 62

Middlemen that allow for visual output to be displayed.

Front 63

What's the capacity/access of a disk?

Back 63

Large capacity, slow access.

Front 64

What's the capacity/access of memory?

Back 64

Reasonable capacity, fast access.

Front 65

What's the capacity/access of cache?

Back 65

Meager capacity, really fast access.

Front 66

Narrows results using this on the command line.

Back 66

*

Front 67

What's a shell?

Back 67

Intermediates between the user and the operating system.

Front 68

Memory allocation for a character:

Back 68

1 byte

Front 69

Memory allocation for an integer:

Back 69

4 bytes

Front 70

Memory allocation for a float:

Back 70

4 bytes

Front 71

Memory allocation for a double:

Back 71

8 bytes

Front 72

Who is Dennis Ritchie?

Back 72

Defined the relatively simple syntax of C as part of the Unix R&D. Wrote the first compiler for C programs.

Front 73

The body of a function is delimited by:

Back 73

braces

Front 74

Used to indicated comments:

Back 74

// blah

or

/* blah */

Front 75

Functions such as printf and scanf are included in which header?

Back 75

#include <stdio.h>

Front 76

Data is stored in ____:

Back 76

bits

Front 77

One value is called a _____:

Back 77

bit

Front 78

Bits are grouped together in groups of _____:

Back 78

eight

Front 79

8 bits equals a _____:

Back 79

byte

Front 80

Why are 8 bits a convenient grouping?

Back 80

They use binary arithmetic (of 1's and 0's)

Front 81

Declares a "small" integer type:

Back 81

short int

Front 82

Declares a "medium" integer type:

Back 82

int

Front 83

Declares a "large" in integer type:

Back 83

long int

Front 84

What's a float?

Back 84

A real (floating point) number.

Front 85

What's a double?

Back 85

A "double precision" floating point number.

Front 86

What's a long double?

Back 86

Even higher precision than a double.

Front 87

What's char?

Back 87

Declares a character of text.

Front 88

What's a "string" of characters equivalent to?

Back 88

An array of single chars.

Front 89

When should variables be defined in the function they are being used?

Back 89

At the beginning

Front 90

What if you do not initialize a defined variable?

Back 90

C doesn't initialize variables and it will reuse memory space when defining a new variable.

Front 91

What's the benefit of using preprocessor definitions?

Back 91

Can speed up your program at run time since fewer vars are stored in memory, meaning few accesses.

Front 92

Why is using const better than defining a variable?

Back 92

The compiler won't let it be altered when the code runs.

Front 93

The "sizeof" statement is used to find out what?

Back 93

The number of bytes used by a variable or data type.

Front 94

Implicit casting is bad because?

Back 94

Data isn't managed by the programmer and it this downward cast would truncate the value of the variable making it have lower precision.

Front 95

How do you cast float variable a into an int i?

Back 95

i = (int) a;

Front 96

What format specifier uses either scientific notation or regular notation, whichever is shorter?

Back 96

%g

Front 97

What are format specifiers?

Back 97

They translate the internal representation of the data into the text on your screen.

Front 98

Makes a new page:

Back 98

\f

Front 99

Moves you back a character:

Back 99

\b

Front 100

Goes to the beginning of the line

Back 100

\r

Front 101

Goes to the next tab stop:

Back 101

\t

Front 102

Rings a bell:

Back 102

\a

Front 103

Prints the character \:

Back 103

\\

Front 104

Prints the character " :

Back 104

\"

Front 105

What does binary operator gives you a remainder?

Back 105

%

Front 106

Logical inequality

Back 106

!=

Front 107

Logical NOT. Invert a test or true/false :

Back 107

!

Front 108

Logical AND

Back 108

&&

Front 109

Logical OR

Back 109

||

Front 110

Any measurable value has a ____ value:

Back 110

true

Front 111

Why do we see a range of measured values?

Back 111

Imperfections and limitations in our instruments and measurements.

Front 112

Define mean:

Back 112

average value of the distributions

Front 113

Define variance:

Back 113

characterizes the width of the data

Front 114

Define standard deviation:

Back 114

Tells us about the distribution of our values. Is the square root of the variance.

Front 115

What matters more, the number of measurements you make or the number of points thrown?

Back 115

NEITHER MATTERS. What matters is just the total number of points in all measurements combined.

Front 116

Each statement must end with a:

Back 116

semicolon (;)

Front 117

Who wrote the g++ compiler?

Back 117

Richard Stallman

Front 118

In the following what is myprogram?

g++ -o myprogram myprogram.cpp

Back 118

An output file which is an executable binary file. You run the program by typing myprogram into the command line.

Front 119

Two ways to write an "if" statement:

Back 119

if(CONDITION){

BLOCK of statements

}

or

if(CONDITION)

statement;

Front 120

If a condition is zero then it is:

Back 120

false

Front 121

If a condition is not zero then it is:

Back 121

true

Front 122

Why can't you use == for floating point numbers?

Back 122

There is limited precision of the calculations.

Front 123

What should one use instead of == for comparing floating point values?

Back 123

Use inequalities to see if the difference between the floating point numbers is less than some threshold.

Front 124

What does the fabs() function do?

Back 124

Returns the absolute value of a floating point number.

Front 125

What does "break" mean in a switch statement?

Back 125

Jumps out of the switch statement and continues with the rest of the program.

Front 126

What happens if you omit a break in a switch statement?

Back 126

The program will continue to work its way through the switch statement, possibly matching other cases.

Front 127

How do you use a "?" operator?

Back 127

CONDITION ? ( true) STATEMENT : (false) STATEMENT;

Front 128

What are count-controlled loops?

Back 128

Used when the user knows beforehand how many times they want to repeat a series of tasks.

Front 129

What are condition-controlled loops?

Back 129

Are used when the user doesn't know how many repetitions will be needed, but that they want to stop when some well-defined thing happens.

Front 130

What are loops?

Back 130

Execute repetitive boring tasks efficiently and accurately over and over.

Front 131

What are the four important parts for a for() loop?

Back 131

Counter initialization, test condition, counter update, and body of execution.

Front 132

What does a "continue" statement do?

Back 132

Skips the rest of the current loop and goes directly to the next iteration.

Front 133

What's the syntax for a "do" loop?

Back 133

do {

BLOCK of statements

} while (CONDITION);

Front 134

What does it mean to "nest" loops?

Back 134

Place one loop inside of another.

Front 135

What is a variable's scope?

Back 135

Refers to where a variable can be accessed.

Front 136

Define local scope.

Back 136

Variables defined inside a function that are available only in that function

Front 137

Define global scope.

Back 137

Variables that are defined outsides all functions and accessed anywhere.

Front 138

What happens if a variable named is used twice once inside of a function and once globally?

Back 138

The local variable will override the global definition, but only within that function. The global variable is unaffected.

Front 139

What type of scope should you limit your variables to?

Back 139

The smallest scope possible.

Front 140

What's bad with having multiple globally defined variables?

Back 140

They can be manipulated/changed ANYWHERE in your code. It will still run, but it can lead to confusion.

Front 141

What is a pass-by-value function?

Back 141

The initial values of arguments are not allowed to change globally. They can change interior to the function, but those changes are never carried out on the global variable. Copies of the input variables are made but not used beyond the function.

Front 142

What is a pass-by-reference function?

Back 142

Arguments can be values or memory locations. Output can be "returned" through the parameter list. Allows multiples results to be accessible to the rest of program.

Front 143

Format specifier used to print memory addresses:

Back 143

printf(" %p", &variable);

Front 144

What is a pointer?

Back 144

A special kind of variable that holds the memory address of another variable.

Front 145

What happens if you don't put an & when scanning in numbers?

Back 145

scanf wouldn't know the addresses of these variables and it wouldn't be able to modify their contents.

Front 146

What's the advantage of passing pointers as arguments to functions?

Back 146

The user can manipulate an arbitrary number of variables, rather than just return one result.

Front 147

What does a segmentation fault error mean?

Back 147

The computer is trying to access or write in a part of the low lying memory that belongs to the operating system which user made programs don't have permission to.

Front 148

What are static variables?

Back 148

Static variables declared in function blocks are preserved between function calls. They are created at program start up and defined for the duration of the program.

Front 149

What are recursive functions?

Back 149

They are functions that are defined in terms of themselves.

Front 150

All recursive functions must have this condition so that the recursion has a limit:

Back 150

terminating condition

Front 151

How would you define a double vector <1,2,3> as an array?

Back 151

double vector[3] = {1.0,2.0,3.0};

Front 152

What are an arrays indicies?

Back 152

Zero to N-1 (where N is the size of the array)

Front 153

How do types work with array?

Back 153

The elements of an array can be any type but all elements of an array must be the same time.

Front 154

When defining an array where do you place the the number of elements within the array?

Back 154

inside the square brackets

Front 155

What type must an array index be?

Back 155

An integer

Front 156

What is the most common source of run-time errors when using arrays?

Back 156

C doesn't check your array indices to make sure they're within the array.

Front 157

When passing an array to a function do you specify the size in the square brackets?

Back 157

NO

Front 158

When passing an array to a function how do you specify the size?

Back 158

Declare a function:

void print_stuff (float a[], int size);

Inside the main:

int max = 20;

float an_array[max];

print_stuff(an_array, max);

Front 159

How do you make a 2D array?

Back 159

Specify two indices.

ex: double matrix[nrow][ncol];

Front 160

What is a consequence of defining an array of any size?

Back 160

The footprint of that array's size is dedicated in the computer's memory. Can easily exhaust a computer's memory by defining arrays that are too large.

Front 161

What is an array of characters?

Back 161

A string

Front 162

An array is equivalent to a _____:

Back 162

pointer

Front 163

Why don't we need to put an & in front of names of character strings?

Back 163

These variables are already pointers.

Front 164

How do you set up your condition for int main() so that it can take arguments from the command line?

Back 164

int main( int argc, char *argv[ ])

Front 165

What is argc?

Back 165

Is the "argument count", the number of arguments the operating system is giving us.

Front 166

What is argv?

Back 166

Is the "argument vector", which is an array of character strings.

Front 167

All arguments are read into memory as:

Back 167

text strings

Front 168

Text strings can be accessed via:

Back 168

argv

Front 169

What is the first arguments when making an array from the command line?

Back 169

The program name. Has index zero (first index).

Front 170

Converts text to an integer:

Back 170

atoi

Front 171

Converts text to a double:

Back 171

atof

Front 172

Converts text to a long:

Back 172

atol

Front 173

Converts text to a float:

Back 173

atoff

Front 174

When defining header files angle brackets (<>) are reserved for what type?

Back 174

Reserved for files in the "standard" system directories.

Front 175

How do you include a code you wrote called, oldcode.cpp ?

Back 175

#include "oldcode.cpp"

Front 176

What's a drawback of include your old code?

Back 176

The computer has to compile the extra code as well.

Front 177

What is an object file?

Back 177

It is compiled code that hasn't been fully processed into a program.

Front 178

Make (compile) an object file for sqrtn.cpp

Back 178

g++ -O -Wall -c sqrtn.cpp

Front 179

If you compile a code into an object file what is the output?

Back 179

file.o

Front 180

If you have a precompiled object file how would you include that into a code?

Back 180

#include "file.hpp"

Front 181

What do function pointers allow you to do?

Back 181

Allow you to pass functionality around your program like data.

Front 182

What is the bolded part of the following:

double (*f) (double x)

Back 182

The pointer points to a function that return a "double".

Front 183

What is the bolded part of the following:

double (*f) (double x)

Back 183

The name of the function pointer is "f". The name must be enclosed in parentheses.

Front 184

What is the bolded part of the following:

double (*f) (double x)

Back 184

This pointer points to a function that takes one argument, of type "double".

Front 185

What format specifier only print in scientific notation?

Back 185

%e