<algorithm>
The header <algorithm> defines a collection of functions especially designed to be used on ranges of elements using iterators.
A range is any sequence of objects that can be accessed through iterators or pointers, such as an array or an instance of some of the STL
containers. Notice though, that algorithms operate through iterators directly on the values, not affecting in any way the structure of any possible
container (it never affects the size or storage allocation of the container). A range is [first, last) – include first, do not include last.
Non-modifying sequence operations:
count
count number of times a value is found in a range
int count (InputIterator first, InputIterator last, const T& val);
int myCount = count (myints, myints+8, 10); //count number of 10’s in the range
count_if
Returns the number of elements in range satisfying a condition
int count (InputIterator first, InputIterator last, UnaryPredicate pred);
//count values for which isOdd returns true
int myCount = count_if (vec.begin(), vec.end(), IsOdd);
find
Find a value in range
InputIterator find (InputIterator first, InputIterator last, const T& val);
it = find (myDeque.begin(), myDeque.end(), 30);
for_each
Apply a function to every element in a range
Function for_each (InputIterator first, InputIterator last, Function fn);
for_each (myList.begin(), myList.end(), square);
Modifying sequence operations:
copy
Copy a range of elements to destination
OutputIterator copy (InputIterator first, InputIterator last, OutputIterator result);
copy (myints, myints+10, myvector.begin());
copy (myints, myints+10, ostream_iterator<int>(cout, “ “));
generate
Generate values for a range of elements using a function
void generate (ForwardIterator first, ForwardIterator last, Generator gen);
generate (myVector.begin(), myVector.end(), UniqueNumber);
random_shuffle
Randomly rearrange elements in a range using a built-in random number generator
void random_shuffle (raIterator first, raIterator last);
random_shuffle (myVector.begin(), myVector.end());
Sorting:
binary_search
Test to determine if a value exists in a sorted sequence
bool binary_search (ForwardIterator first, ForwardIterator last, const T& val);
if (binary_search (v.begin(), v.end(), 3)) cout << “value was found” << endl;
sort
Sort elements in a range
void sort (RandomAccessIterator first, RandomAccessIterator last);
sort (myDeque.begin(), myDeque.end());
Min/Max:
min_element
Return the smallest element in a range
ForwardIterator min_element (ForwardIterator first, ForwardIterator last);
cout << "The smallest element is " << *min_element(myints, myints+7) << endl;
max_element
Return the largest element in a range
ForwardIterator max_element (ForwardIterator first, ForwardIterator last);
cout << "The largest element is " << *max_element(myints, myints+7) << endl;
Numeric:
requires #include <numeric>
Accumulate
Accumulate values in a range
T accumulate ( InputIterator first, InputIterator last, T iniitialValue );
cout << accumulate(numbers, numbers+3, 0); //initial value of accumulation is 0