Exam 2 Topics

Question 1

What are the two types of flow of control and define them.

Answer 1

sequential is when the statements are executed in the order they are placed in a program.

selection structure allows a program to choose between alternative actions.

Question 2

What are the two selection statements in C++

Answer 2

They are “if” and “switch”

Question 3

What is the “if” statement syntax. (two-way selection)

Answer 3

if (logical expression)
statement1;
else
statement2;

Question 4

Define what “logical expression” is.

Answer 4

an expression that evaluates to true or false

Question 5

Define what a “bool” is

Answer 5

built-in data type for storing logical values. Can be either true or false. non-zero is true, zero is false.

Question 6

Handwrite the relational operators used to compare values to each other

Answer 6

< > <= >=

== !=

Question 7

Handwrite the logical operators that are used to change or connect logical exprfessions

Answer 7

! – not && - and || - or

Question 8

What is short circuit evaluation

Answer 8

process in which a computer evaluates a logical expressio0n from left to right and stops as soon as the final value of the expression is known

Question 9

What is a switch statement

Answer 9

A switch statement provides multi-way selection, can be used in place of a nested if else structure if expression being tested is discrete (integral)

Question 10

Handwrite the syntax for a switch statement

Answer 10

switch (expression) 
{
 case value1: statements1; 
                    break;
case value2: statements2;
                   break;
 . . .
 case valuen: statementsn;
                      break;
 default: statements; 
                    break;
}

Question 11

What does “mv” command do? (Linux commands)

Answer 11

it is used to change the name of a file.

mv oldfile newfile will change the name of oldfile to newfile in the current directory (assuming oldfile exists)

Question 12

what does “rm” command do? (Linux commands)

Answer 12

used to permanently delete a file

rm afile will delete a file from the current directory (assuming the file exists)

Question 13

What does “mkdir” command do? (Linux commands)

Answer 13

used to create a directory (will be subdirectory of current directory)

mkdir exercises will create a directory called exercises

Question 14

what does “cd” command do? (Linux commands)

Answer 14

used to move from one directory to another

cd exercises will move from current directory to the exercises directory

cd will return to home directory

Question 15

What does “pwd” command do? (Linux commands)

Answer 15

displays absolute path to current directory - use it to figure out where you are

Question 16

what does “rmdir” command do? (Linux commands)

Answer 16

used to delete a directory - the directory must be empty

rmdir exercises will remove the exercises directory

Question 17

Define “Batch processing”

Answer 17

all input is gathered together and palced in a file (a batch), program is deigned to read the data from the file as needed (no prompting required)

Question 18

Define “Input failure”

Answer 18

if the data type of a variable and the value being read into it do not match, the input operation will stop working. Once input failure occurs, not further read operations will be executed. generally, the program will continue running

Question 19

What is the “get” function and what does it do?

Answer 19

a function that can be used to read character data, including white space (defined in iostream)

cin.get(ch);

Question 20

What is “Linux redirection for bath processing” and what are the two operators that control it?

Answer 20

”” linux output redirection operator changes the default output destination to a specified file

./a.out < input > output

Question 21

Define “repetition structure”

Answer 21

statement that allows for an action to be repeated (iteration, looping)

Question 22

List the three C++ repetition statements

Answer 22

for, while, do while

Question 23

Define “counting” and two operators that can be used for it.

Answer 23

looping often involves counting things

++ increment operator- unary operator used to add 1 to a variable

– decrement operator - unary operator used to subtract 1 from a variable

Question 24

What is a “for statement”

Answer 24

a statement specifically designed for implementing count-controlled loops

Question 25

What is a “count controlled loop”?

Answer 25

a loop designed to execute a specific number of times, number of runs is determined before loop starts.

Question 26

Handwrite the general syntax for a “for loop”

Answer 26

for (initial statement; loop condition; update statement)

action; // loop body

Question 27

Define “Nested looping”

Answer 27

when processing one data set requires repetition, and there are several data sets, loops can be nested.

Question 28

Define “while” statement

Answer 28

a general conditional looping statement.

Question 29

What is a conditional loop?

Answer 29

they are used when the number of repetitions required is not known in advance

Question 30

Handwrite the general syntax for a “while loop”

Answer 30

while (logical expression)

statement;

Question 31

Define a “infinite loop” and how to exit one.

Answer 31

if the logical expression in a while statement remains always true, the loop will not be exited. To exit an infinite loop use ctrl-c

Question 32

Name two common conditional looping situations

Answer 32

eof-controlled and sentinel controlled

Question 33

Define “eof-controlled”

Answer 33

designed to read and process data until the end-of-file is encountered. use cin as logical expression for eof control.

Question 34

Define “sentinel-controlled”

Answer 34

can be used when the last entry in a data setis a special value (setinel) that indicates when the loop should stop

Question 35

What is the general set up for a sentinel-controlled while loop?

Answer 35

read first data value

while data is not the sentinel

perform action to be repeated

read next data value

Question 36

Define “value-returning function”

Answer 36

a function designed to compute and return exactly one value using a return statement. must include a return statement

Question 37

Define “void function”

Answer 37

a function containing a series of statements designed to perform a task. This function does not have a specific data type

Question 38

List the three things that are needed to add a function to a C++ program

Answer 38

function definition, function prototype, and function call

Question 39

Define “function definition”

Answer 39

consists of a heading and a body, placed after the main function

Question 40

Define “function prototype”

Answer 40

placed after using statement and const declarations, before heading for main func tion - provides information to compiler about the function

Question 41

Define “function call”

Answer 41

placed inside any function, used when you want the statements in the function to be executed

Question 42

Name the three typical situations when a void function is appropriate.

Answer 42

function will generate some type of output

function performs a task that does not directly result in the calculation of a single value

function performs a task that involves changing one or more values passed to it

Question 43

Define “parameter”

Answer 43

a parameter is a value that is passed (communicated) to a function and should be the only way that functions share data

Question 44

Name the two methods of parameter passage

Answer 44

pass by value and pass by reference

Question 45

Define “pass by value”

Answer 45

a copy of the value of the actual parameter (which is supplied in the function call) is transmitted to the function for its use

Question 46

Define “pass by reference”

Answer 46

the memory location of the actual parameter (which is supplied in the function call) is sent to the function. The function will change the literal value of the memory location.

Question 47

Define function documentation

Answer 47

for each function provide a brief statement with the definition of the input output and what the function does

Question 48

Define “function prototype”

Answer 48

serves as the declaration to the compiler for a function. specifies the functions type, name, and parameter list. Should be placed before the main function.

Question 49

Hand write the syntax for a function prototype

Answer 49

function_type function_name(parameter list);

Question 50

Define “function call”

Answer 50

a statement used to invoke a function (cause it to be executed)

Question 51

Hand write the syntax for calling a function.

Answer 51

function_name(actual parameter list)

Question 52

Define “local variable”

Answer 52

a variable declared inside a function or program block is said to be local to the function/block. Exists inside a function/block only.

Question 53

Define “Scope of an identifier”

Answer 53

it is the region (part) of a program where an identifier is recognized (visible) and accessible

Question 54

Define “local identifier” and how its memory is allocated

Answer 54

identifier declared within a function (or block). The memory is allocated at declaration and de-allocated at block exit (automatic allocation)

Question 55

Define “Global identifier” and how its memory is allocated

Answer 55

identifier declared outside of every function definition. The memory is allocated at declaration and de-allocated when program is finished executing (static allocation)

Question 56

What are the general scope rules for when a global identifier is accessible by a function or block?

Answer 56

the identifier is declared before the function(block).

the function name is different from the global identifier name

all parameters have names different from the global identifier name

all local identifiers have names different from the global identifier name

Question 57

What are the general scope rules for when a identifier declared within a block is accessible?

Answer 57

from the point it is declared to the end of the block in which it is declared

in any nested blocks that do not have an identifier with the same name

Question 58

Define “Side effect”

Answer 58

it is a unintended change to a variable, use of global variables can lead to side effects (don’t use global variables)

Question 59

What is the scope of a function name

Answer 59

Scope of a function name is the same as the scope of a global identifier.

Question 60

What is the scope of a formal parameter?

Answer 60

Scope of a formal parameter is the function in which it is declared.