Final Exam

Question 1

List 3 limitations with C-style strings.

Answer 1

1) Forgetting to end string with ‘\0’
2) Not allocating enough memory for string
3) Cannot add, delete, or combine elements

Question 2

What is the preprocessor directive for strings?

Answer 2

include

Question 3

What are two ways to initialize a string variable?

Answer 3

string name = "Mike";
or
string name("Mike");

Question 4

How do you use string concatenation?

Answer 4

Use + operator.

fullname = firstname + lastname;

Question 5

What is the preprocessor directive for writing to files?

Answer 5

include

Question 6

What are the five steps of writing to a file?

Answer 6

1) Create an output stream object
2) Establish connection to file
3) Verify connection
4) Start writing
5) Close file

Question 7

What is the syntax for declaring an output stream object?

Answer 7

ofstream fout;

Question 8

What is the syntax for opening a file?

Answer 8

fout.open(“filename.txt”, ios::out);

Question 9

What is the syntax for verifying an output stream connection?

Answer 9

if(!fout.is_open())
{
// cerr & exit
}

Question 10

What is the syntax for closing a file?

Answer 10

fout.close();

Question 11

When do you need to convert a string to a c-sring and what is the syntax for converting a C++ string to C-style string?

Answer 11

Convert to c-string when using a string as the file name in an output file stream.

Syntax: stringName.c_str();

Question 12

What is the function that returns the size of a string?

Answer 12

stringName.length()

Question 13

What is the function that returns the size of a vector?

Answer 13

vectorName.size()

Question 14

What is the preprocessor directive needed to use the sort function?

Answer 14

include

Question 15

What is the syntax of the sort function?

Answer 15

sort(list.begin(), list.end());

Question 16

What are two drawbacks to vectors?

Answer 16

1) Vectors take up more memory

2) Could take more time

Question 17

When should arrays be used over vectors?

Answer 17

When the array is of a fixed size and when speed is an issue

Question 18

What is the major limitation of arrays?

Answer 18

Size is constant and cannot be changed. Therefore, you might have allocated memory for the array that you did not use.

Question 19

What are the six steps of reading a file?

Answer 19

1) Know the format of the file.
2) Create an input stream object (input file handler)
3) Establish connection to file.
4) Verify connection.
5) Start reading.
6) Close the file.

Question 20

What is the syntax of creating an input stream object/input file handler?

Answer 20

ifstream fin;

Question 21

What is the syntax of opening a file for reading?

Answer 21

fin.open(“filename.txt”, ios::in);

Question 22

What is the syntax for verifying connection to an input file handler?

Answer 22

if (!fin.is_open())
{
// cerr & exit
}

Question 23

What is the syntax for reading data from a file into a variable x?

Answer 23

fin&raquo_space; x;

Question 24

What is the syntax for closing an input file stream?

Answer 24

fin.close();

Question 25

What is the syntax for reading a file until the read fails?

Answer 25

fin >> x;
while (!fin.fail())
{
cout > x;
}

Question 26

When will the function fail() return true?

Answer 26

1) End of file is reached, or

2) Read error: trying to read the wrong data type

Question 27

What is the simpler equivalent to using the fail() function in a while loop?

Answer 27

while (fin)

Question 28

How can you check for a read error (i.e. fail function returns true before the end of a file)? Describe syntax.

Answer 28

if (!fin.eof())
{
// cerr and exit
}

Question 29

What are some common errors in fstream?

Answer 29

1) Writing to a file which was opened for reading
2) Reading a file which was opened for writing
3) Forgetting to open/close a file
4) Not checking for read failure

Question 30

What is the difference between using ofstream and ostream when passing file streams?

Answer 30

ofstream can pass fout, but ostream can pass cout or fout

Question 31

What is the syntax for initializing a vector of 5 items and initializing all items to -1.0?

Answer 31

vector list(5, -1.0);

Question 32

What are two ways to initialize a C-style string?

Answer 32

char s[] = “Hello”;
or
char s[5] = { ‘H’, ‘e’, ‘l’, ‘l’, ‘o’, ‘\0’ }

Question 33

What is the syntax for removing the last element of a vector?

Answer 33

vectorName.pop_back();

Question 34

Write syntax for passing an array so that it can be edited.

Answer 34

function(int arrayName[]);

Question 35

Write syntax for passing an array so that it cannot be edited.

Answer 35

function(const int arrayName[]);

Question 36

Write syntax for passing a vector so that it can be edited.

Answer 36

function(vector & list);

Question 37

Write syntax for passing a vector so that it cannot be edited.

Answer 37

function(const vector & list);

Question 38

Write syntax for passing a string so that it can be edited.

Answer 38

function(string & name);

Question 39

Write syntax for passing a string so that it cannot be edited.

Answer 39

function(const string & name);

Question 40

Write syntax for using an array with dynamic memory allocation.

Answer 40

int n;
int * x;

n = 4;
x = new int[n];

…

delete [] x;

Question 41

What is it called when dynamic memory allocation is not deleted?

Answer 41

memory leak

Question 42

What is the output?

int x = 8;
cout

Answer 42

address of x is outputted

Question 43

What is the output?

int x = 8;
int *ptr = &x;
cout

Answer 43

address of x is outputted

Question 44

What is the output?

int x = 8;
int *ptr = &x;
cout

Answer 44

8

Question 45

What are the two types of memory, and describe them.

Answer 45

1) Static memory: determined at compile time, allocated on program execution
2) Dynamic memory: allocated at run-time

Question 46

Describe the syntax of the string replace function.

Answer 46

s.replace(6, 3, “Hi”);

Replaces starting with the 6th index, replaces 3 places with “Hi”

Question 47

Describe the syntax of the string insert function.

Answer 47

s.insert(6, “Hi”);

Inserts before the 6th index, inserts “Hi”

Question 48

Write a replace function to change the string “Hello World” to “Hello Mars”

Answer 48

s.replace(6, 5, “Mars”);

Question 49

Write an insert function to change the string “Hello World” to “Hello Beautiful World”

Answer 49

s.insert(6, “Beautiful “);