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CSE390C Final Cheat Sheet handout #6
some common string operations:
output << str; insert str onto output stream
input >> str; extract str from input stream (one token)
getline(input, str) read into str one line from input
str.empty() is str empty?
str.size() how many characters in str?
str[index] reference to character at given index
str1 + str2 result of adding two strings (a new string)
==, !=, <, >, <=, >= relational operators to compare two strings
istringstream input(str) make an input stream from the given string
str.substr(index, n) string of n characters starting at index
str.substr(index) string of characters starting at index
str.find(str2) first occurrence of str2 in str or -1
str.rfind(str2) last occurrence of str2 in str or -1
some common vector operations:
v.push_back(n) append n to end of vector
v.empty() is v empty?
v.size() how many elements in v?
v[index] reference to value at given index
==, != compares all values for equality
some common stream operations:
ifstream input(name); initializes ifstream to read from given file
ofstream output(name); initializes ofstream to write to given file
stream >> x; read (extract) x from given input stream
stream << x; write (insert) x to given output stream
getline(input, str) read into str one line from input
stream.open(name); opens the stream to the given file
stream.close() closes the stream
istringstream input(str) make an input stream from the given string
ostringstream output() make an output stream that will go to a string
stream.str() convert an ostringstream to a string
some common math functions:
abs(x) returns the absolute value of x
max(x, y) returns the larger of x and y
min(x, y) returns the smaller of x and y
pow(x, y) returns the value of x to the power of y
round(n) rounds to the nearest integer
sqrt(n) returns the square root of n
Basic Operations of STL structures:
function/operator vector list set multiset
---------------------------------------------------------
push_back(value) x x - -
push_front(value) - x - -
insert(value) - - x x
back() x x - -
front() x x - -
pop_back() x x - -
pop_front() - x - -
x[index] x - - -
size() x x x x
empty() x x x x
clear() x x x x
==, !=, <, >, <=, >= x x x x
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Use of iterators STL structures:
function/operator vector list set multiset
---------------------------------------------------------
begin() x x x x
end() x x x x
*iterator (const) x x x x
*iterator (reference) x x - -
iterator+n and +=n x - - -
iterator-n and -=n x - - -
erase(iterator) x x x x
insert(iterator, value) x x x x
Basic operations on maps:
function/operator
-----------------
insert(pair)
x[index] (reference to the value associated with this key)
size()
empty()
clear()
count(key) (returns a count of the # of keys equal to key, always 0 or 1
Use of iterators on maps:
function/operator
----------------------
begin()
end()
*iterator (const)
erase(iterator)
insert(iterator, value)
pair<type1, type2>
first--returns first element in the pair
second--returns second element in the pair
use type unordered_set for a set of objects that do not overload operator <
use type unordered_map for a map whose keys do not overload operator <
Examples of available algorithms:
find(start, end, value) first occurrence in [start, end) or end if not
found
count(start, end, value) number of occurrences of value in [start, end)
equal(start1, end1, whether values in [start1, end1) are all equal
start2, end2) to the values in [start2, end2)
replace(start, stop, replaces all occurrences of old with new in
old, new) [start, end)
reverse(start, stop) reverses the order of the elements [start, end)
random_shuffle(start, stop) randomly shuffles values in [start, end)
sort(start, end) sorts elements from [start, end)
is_sorted(start, stop) returns whether values in range are sorted
merge(start1, stop1, merges sorted [start1, stop1) with sorted
start2, stop2, start3) [start2, stop2), storing in start3
accumulate(start, stop, s) sum of values in [start, stop), init sum s
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