Manipulating A C - STRINGS AS AN ARRAY OF CHARACTERS

Question 1

testing the value of a character

Answer 1

functions test a single char argument for a specific quality and return true or false

Question 2

isupper

Answer 2

function in the header that tests to see if a character is an uppercase letter

Question 3

isalpha

Answer 3

function in the header that tests to see if a character is a letter of the alphabet

Question 4

isalnum

Answer 4

function in the header that tests to see if a character is a letter of the alphabet or a digit

Question 5

isdigit

Answer 5

function in the header that tests to see if a character is a digit from 0 to 9

Question 6

islower

Answer 6

function in the header that tests to see if a character is a lowercase letter

Question 7

isprint

Answer 7

function in the header that tests to see if a character is a PRINTABLE CHARACTER including a space (basically as far as I can tell, not the null terminator)

Question 8

ispunct

Answer 8

function in the header that tests to see if a character is a PRINTABLE CHARACTER other than a digit, letter, or space

Question 9

isspace

Answer 9

function in the header that tests to see if a character is a whitespace characterspace ‘ ‘newline \nvertical tab \vtab \t

Question 10

toupper

Answer 10

function in the header that returns the uppercase equivalent of a char-type argument (w/o changing the original as per C++ usual). Will return an uppercase letter or nonletter argument unchangedcout &laquo_space;toupper(‘a’) for instance

Question 11

tolower

Answer 11

function in the header that returns the lowercase equivalent of a char-type argument (w/o changing the original as per C++ usual). Will return a lowercase letter or nonletter argument unchangedcout &laquo_space;tolower(‘A’) for instance

Question 12

string

Answer 12

generic term that describes any consecutive sequence of characters

Question 13

C-string

Answer 13

string whose characters are stored in consecutive memory locations and are followed by the null terminator (ASCII 0). Basically a char array with space for each character, +1 for the null terminatorString literals/constants are stored as C-strings

Question 14

implicit sizing - char array

Answer 14

“since a string literal is itself read as an array, and the computer notices the number of characters, you can initialize an array with a string literalchar characterarray[] = ““Grace”” which will have 6 spotsand those spots will be filled byG r a c e \0but you can write over them”

Question 15

c-string console input

Answer 15

“char characterarray[21];cin&raquo_space; characterarray;in the second line, ““characterarray”” is a variable that represents the array with the pointer at the beginning of itcin will write past the end of the array if you cin more than 21 characters. I think this is called overloading. in any case, cin.getline()”

Question 16

cin.getline() for c-strings and character arrays

Answer 16

cin.getline(stordes, MAXLN);and then you type stuff and hit ENTER when you’re donestordes is the storage destination. Because it’s a string literal, it’ll be stored in a character array. The name of the array by itself represents the array with the pointer reset to index at 0.maxln (constant integer) is the maximum length of the input, so usually the size of the array. Because the input includes the null terminator, an 80-index array will intake 79 values. If the input isn’t that long, it’ll append the null terminator at the end of the input.it does NOT truncate the array to the size of the string

Question 17

strlen

Answer 17

“function in the header that returns the length of the c-string argument. NOT counting the null terminator nor the size of the arrayargument can be name of the array, pointer variable (later), or the string literalbecause the argument is the name of the array (not the array w/indexed size), the pointer is set to the beginning so it doesn’t know the size of the array after the null terminatorlength = strlen(arrayname) or =strlen(““Grace””)”

Question 18

sizeof

Answer 18

I’m sure I wrote this down in a previous chapter but this counts the value spots in an array (different than strlen!)

Question 19

strcat

Answer 19

function in the header that concatenates one string to another. Argument is two C-strings (using their array names sans indices). Be sure to put a space in one of the string literals, because strcat won’t insert it and there’s no space to add it as an argumentcopies the 2nd string over to the end of the 1st. Leaves the 2nd string (saved under its own name) alone, but 1st is changedstrcat(string1, string2);this can overload the bounds of an array

Question 20

strncat

Answer 20

function in the header that works like strcat but there’s a third argument specifying the max number of characters from 2nd string to append to 1st stringstrncat(string1, string2, 10);

Question 21

strcpy

Answer 21

function in the header that writes one string over another without a loop (or copies a string to an array). I assume this would be used to take one string, multiply it or something, then strcpy it to a new column in a structure or somethingstrcpy(string1, string2);this can overload the bounds of an array

Question 22

strncpy

Answer 22

function in the header that works like strcpy but there’s a third argument specifying the max number of characters from 2nd string to copy to the 1ststrncpy(string1, string2, 5);*come back to this

Question 23

strstr

Answer 23

“function in the header that searches for a string inside of a string. First argument is the string to be searched and the second is what you’re looking for. It’ll search a c-string character array and return address of the first character of the second stringstring1 = ““blood types A B AB O”“strstr(string1, ““AB”“)I don’t know what would happen if I searched just for A or Bbut apparently it returns the rest of string 1 after starting at the beginning of string 2”

Question 24

strcmp

Answer 24

“function in the header (?!?! maybe this is a typo) that compares c-strings, since relational operators won’t workstrcmp(string1, string2)This function will return 0 if the strings are equal on a character-by character basis,-1 if string1 comes BEFORE string2 in alphabetical order1 if string1 comes AFTER string2 in alphabetical orderthis works well with if statements, and you can use the returns with relational operatorsusing ! - the computer sees 0 as false. If your strings are equal, and you want the computer to report ““true”” for that (just because it’s more intuitive) put ! in front of the callif (!strcmp(string1, string2))I don’t think that works if the strings aren’t equal but I’ll test it”

Question 25

stricmp

Answer 25

function in the header (?!?! maybe this is a typo) that compares c-strings with no case sensitivity

Question 26

sort strings

Answer 26

use strcmp or stricmp to put strings in alphabetical orderif(strcmp(string1, string2) <0 {cout &laquo_space;string1 &laquo_space;’ ‘ <remember, -1 means they’re already in alphabetical order

Question 27

c++ string type (also known as a string object, as opposed to a string literal)

Answer 27

“abstract data type/class. Be sure to #include then define it asstring stringName; and assign it withstringName = ““Contents Go Here””; and you can just work with stringName like you would another char variable”

Question 28

reading into a C++ string

Answer 28

string stringName;getline(cin, stringName);

Question 29

relational and math operators w/C++ strings

Answer 29

, >=, ==, and != compare the ASCII values of the characters in each string, one by oneI don’t know how this works for lower- versus uppercaseyou can use relational operators to compare C++ strings with C strings but as far as I can tell it has to be a string literalstringOne += stringTwo appends a copy of stringTwo to end of stringOnestringOne + stringTwo concatenates the two strings //how is this different from +=? I guess you can save this as a new var

Question 30

assigning a string variable (methods)

Answer 30

“string stringName; //emptystring stringName(““here it is””);string newString(stringName); //copy of stringNamestring newString(stringName, 10); //first 10 valuesstring boring(‘z’, 10); //10 z’s in a stringstring middleName(fullName, 5, 10); the values of fullName from 5 to 10”

Question 31

string subscripts []

Answer 31

work just like in a C-string arraycplusplusString[0] etc

Question 32

length

Answer 32

function in the header that returns the length of the string ~stored in the object~ (what does that mean?)newString.length();

Question 33

size

Answer 33

function in the header that returns the length of the string as well (I’m sure this is the spiritual child of sizeof instead of strlen)newString.size();

Question 34

append

Answer 34

“function in the header that appends ““n”” copies of ‘z’ to newStringnewstring.append(n, ‘z’);or character-array-slash-string-object chr newstring.append(chr);or the first n characters of chrnewstring.append(chr, n);or a selection of 5 values from chr starting at 20 herenewstring.append(chr, 20, n); //if newstring is too small, it’ll fill it as much as possible (won’t overflow)”

Question 35

assign

Answer 35

function in the header that assigns n copies of ‘z’ to the string. I think it’ll write over existing stuff but I’d use this w/empty strings anywaynewstring.assign(n, ‘z’);assigns a string or character array thing_assigned to newstring.assign(thing_assigned);assign the first n characters of thing_assigned to newstringnewstring.assign( thing_assigned, n);assign 5 many characters from thing_assigned starting at 20, to newstring. If newstring is too small, the function will assign as many as possible (won’t overflow)newstring.assign(thing_assigned, 20, 5);

Question 36

at

Answer 36

function in the header that returns the character at position 3 (or whatever) in the stringnew_string.at(3);

Question 37

begin

Answer 37

function in the header that returns an iterator (ch16?) pointing to the first character in the stringnew_string.begin();

Question 38

c_str

Answer 38

function in the header that converts the contents of new_string to a C-string and returns a pointer to the beginning of it. WHY THOnew_string.c_str();

Question 39

capacity

Answer 39

function in the header that returns the size of the storage allocated for new_string (in what units? bytes?)new_string.capacity();

Question 40

clear

Answer 40

function in the header that deletes everything in the string. Be darned careful