OOP2 Strings

Question 1

What type of data type is the string type?

Answer 1

Programmer defined type, not part of base C++

Question 2

What library do you need to access std::string data type?

Answer 2

include <string></string>

Question 3

What terminators do you need for strings?

Answer 3

“ … “

Question 4

What are strings called with no characters?

Answer 4

Null/empty strings

Question 5

What does length function do for std::string?

Answer 5

Returns unsigned int of how many chars are in string

Question 6

What does size function do?

Answer 6

Returns unsigned int value of amount of chars in the string, same as .length() but works also with vector, arrays etc

Question 7

What type is the unsigned int returned by length, size, etc?

Answer 7

std::string::size_type

Question 8

What does .find() do?

Answer 8

Find returns an int of type string::size_type corresponding to the index of the string where the first char of the passed string was matched

Question 9

What argument does .find() take?

Answer 9

It takes a substring to be found in the operated string

Question 10

Find is case sensitive, true or false?

Answer 10

True

Question 11

What happens if .find() finds no match?

Answer 11

Returns an named const of type string::npos

Question 12

What happens if there are multiple identical subtrings for .find() to find?

Answer 12

Considers only the first

Question 13

What does .substr() do?

Answer 13

Returns the piece of the string that starts at the specified index and continues for the number of chars specified

Question 14

What arguments does .substr() take?

Answer 14

Substring takes two integers, first is starting index, second is length of sub string

Question 15

Where does substring start counting from for length of returned string?

Answer 15

1 counted from same index as first argument

Question 16

What does .at() function do?

Answer 16

Returns char at index of passed argument

Question 17

What argument does .at() function take?

Answer 17

It takes an integer type and uses it as index value

Question 18

How is string type different from char arrays / c strings in terms of
1. program runtime integrity,
2. in terms of how they are terminated?

Answer 18

1. Strings have bound checking at compile time, arrays do not
2. Strings are terminated with the enclosing speech marks, char arrays / c strings are terminated with the null character

Question 19

What library is needed for toupper() and tolower()?

Answer 19

include <cctype></cctype>

Question 20

What arguments do toupper() and tolower() take?

Answer 20

A single char data type

Question 21

Other than .at(), how can you access chat at index?

Answer 21

std::string myString = “hello”;
ch = myString[4];
ch will contain ‘o’

Question 22

How to concentrate strings?

Answer 22

+ operator or .append()

Question 23

What does .compare() return?

Answer 23

0 if they are equal,
< 0 if the the passed string is shorter/first character doesn’t match
> 0 if the passed string is longer or first unmatching char is longer

Question 24

What does .insert() take?

Answer 24

2 arguments: 1. Index, 2. String

Question 25

How to obtain a cstring from a string?

Answer 25

myString.c_str();

Question 26

How to clear a string and leave it empty/null?

Answer 26

myString.erase();

Question 27

.replace takes?

Answer 27

Three arguments, first index where to start, second index where to end, third the string to replace with

Question 28

.begin() and .end()?

Answer 28

Returns the index of the beginning and past-the-end characters of strings

Question 29

.swap()?

Answer 29

Exchanges the content of two strings

Question 30

.pop_back()?

Answer 30

Deletes last char of string

Question 31

.push_back()?

Answer 31

Adds a new character at end of string, takes a single character as argument

Question 32

Difference between [] and .at()?

Answer 32

[] does not bound check but does not throw an error,
.at() bounds checks

Question 33

Erase takes two optional arguments. What is it?

Answer 33

Int for index from which to erase, and int for length for how long to erase