<algorithm>

Defines C++ Standard Library container template functions that perform algorithms.

Syntax

(see relevant links below for specific algorithm syntax)

Remarks

The C++ Standard Library algorithms are generic because they can operate on a variety of data structures. The data structures that they can operate on include not only the C++ Standard Library container classes such as vector and list, but also program-defined data structures and arrays of elements that satisfy the requirements of a particular algorithm. C++ Standard Library algorithms achieve this level of generality by accessing and traversing the elements of a container indirectly through iterators.

C++ Standard Library algorithms process iterator ranges that are typically specified by their beginning or ending positions. The ranges referred to must be valid in the sense that all pointers in the ranges must be dereferenceable and, within the sequences of each range, the last position must be reachable from the first by incrementation.

The C++ Standard Library algorithms extend the actions supported by the operations and member functions of each C++ Standard Library container and allow working, for example, with different types of container objects at the same time. Two suffixes have been used to convey information about the purpose of the algorithms.

  • The _if suffix indicates that the algorithm is used with function objects operating on the values of the elements rather than on the values of the elements themselves. The find_if algorithm looks for elements whose values satisfy the criterion specified by a function object, and the find algorithm searches for a particular value.

  • The _copy suffix indicates that the algorithm not only manipulates the values of the elements but also copies the modified values into a destination range. The reverse algorithm reverses the order of the elements within a range, and the reverse_copy algorithm also copies the result into a destination range.

C++ Standard Library algorithms are often classified into groups that indicate something about their purpose or requirements. These include modifying algorithms that change the value of elements as compared with non-modifying algorithms that do not. Mutating algorithms change the order of elements, but not the values of their elements. Removing algorithms can eliminate elements from a range or a copy of a range. Sorting algorithms reorder the elements in a range in various ways and sorted range algorithms only act on ranges whose elements have been sorted in a particular way.

The C++ Standard Library numeric algorithms that are provided for numerical processing have their own header file <numeric>, and function objects and adaptors are defined in the header <functional> Function objects that return Boolean values are known as predicates. The default binary predicate is the comparison operator<. In general, the elements being ordered need to be less than comparable so that, given any two elements, it can be determined either that they are equivalent (in the sense that neither is less than the other) or that one is less than the other. This results in an ordering among the nonequivalent elements.

Function templates

Function template Description
adjacent_find Searches for two adjacent elements that are either equal or satisfy a specified condition.
all_of Returns true when a condition is present at each element in the given range.
any_of Returns true when a condition is present at least once in the specified range of elements.
binary_search Tests whether there is an element in a sorted range that is equal to a specified value or that is equivalent to it in a sense specified by a binary predicate.
copy Assigns the values of elements from a source range to a destination range, iterating through the source sequence of elements and assigning them new positions in a forward direction.
copy_backward Assigns the values of elements from a source range to a destination range, iterating through the source sequence of elements and assigning them new positions in a backward direction.
copy_if Copy all elements in a given range that test true for a specified condition
copy_n Copies a specified number of elements.
count Returns the number of elements in a range whose values match a specified value.
count_if Returns the number of elements in a range whose values match a specified condition.
equal Compares two ranges element by element either for equality or equivalence in a sense specified by a binary predicate.
equal_range Finds a pair of positions in an ordered range, the first less than or equivalent to the position of a specified element and the second greater than the element's position, where the sense of equivalence or ordering used to establish the positions in the sequence may be specified by a binary predicate.
fill Assigns the same new value to every element in a specified range.
fill_n Assigns a new value to a specified number of elements in a range starting with a particular element.
find Locates the position of the first occurrence of an element in a range that has a specified value.
find_end Looks in a range for the last subsequence that is identical to a specified sequence or that is equivalent in a sense specified by a binary predicate.
find_first_of Searches for the first occurrence of any of several values within a target range or for the first occurrence of any of several elements that are equivalent in a sense specified by a binary predicate to a specified set of the elements.
find_if Locates the position of the first occurrence of an element in a range that satisfies a specified condition.
find_if_not Returns the first element in the indicated range that does not satisfy a condition.
for_each Applies a specified function object to each element in a forward order within a range and returns the function object.
generate Assigns the values generated by a function object to each element in a range.
generate_n Assigns the values generated by a function object to a specified number of element is a range and returns to the position one past the last assigned value.
includes Tests whether one sorted range contains all the elements contained in a second sorted range, where the ordering or equivalence criterion between elements may be specified by a binary predicate.
inplace_merge Combines the elements from two consecutive sorted ranges into a single sorted range, where the ordering criterion may be specified by a binary predicate.
is_heap Returns true if the elements in the specified range form a heap.
is_heap_until Returns true if the specified range forms a heap until the last element.
is_partitioned Returns true if all the elements in the given range that test true for a condition come before any elements that test false.
is_permutation Determines whether the elements in a given range form a valid permutation.
is_sorted Returns true if the elements in the specified range are in sorted order.
is_sorted_until Returns true if the elements in the specified range are in sorted order.
iter_swap Exchanges two values referred to by a pair of specified iterators.
lexicographical_compare Compares element by element between two sequences to determine which is lesser of the two.
lower_bound Finds the position of the first element in an ordered range that has a value greater than or equivalent to a specified value, where the ordering criterion may be specified by a binary predicate.
make_heap Converts elements from a specified range into a heap in which the first element is the largest and for which a sorting criterion may be specified with a binary predicate.
max Compares two objects and returns the larger of the two, where the ordering criterion may be specified by a binary predicate.
max_element Finds the first occurrence of largest element in a specified range where the ordering criterion may be specified by a binary predicate.
merge Combines all the elements from two sorted source ranges into a single, sorted destination range, where the ordering criterion may be specified by a binary predicate.
min Compares two objects and returns the lesser of the two, where the ordering criterion may be specified by a binary predicate.
min_element Finds the first occurrence of smallest element in a specified range where the ordering criterion may be specified by a binary predicate.
minmax Compares two input parameters and returns them as a pair, in order of least to greatest.
minmax_element Performs the work performed by min_element and max_element in one call.
mismatch Compares two ranges element by element either for equality or equivalent in a sense specified by a binary predicate and locates the first position where a difference occurs.
<alg> move Move elements associated with a specified range.
move_backward Moves the elements of one iterator to another. The move starts with the last element in a specified range, and ends with the first element in that range.
next_permutation Reorders the elements in a range so that the original ordering is replaced by the lexicographically next greater permutation if it exists, where the sense of next may be specified with a binary predicate.
none_of Returns true when a condition is never present among elements in the given range.
nth_element Partitions a range of elements, correctly locating the nth element of the sequence in the range so that all the elements in front of it are less than or equal to it and all the elements that follow it in the sequence are greater than or equal to it.
partial_sort Arranges a specified number of the smaller elements in a range into a nondescending order or according to an ordering criterion specified by a binary predicate.
partial_sort_copy Copies elements from a source range into a destination range where the source elements are ordered by either less than or another specified binary predicate.
partition Classifies elements in a range into two disjoint sets, with those elements satisfying a unary predicate preceding those that fail to satisfy it.
partition_copy Copies elements for which a condition is true to one destination, and for which the condition is false to another. The elements must come from a specified range.
partition_point Returns the first element in the given range that does not satisfy the condition. The elements are sorted so that those that satisfy the condition come before those that do not.
pop_heap Removes the largest element from the front of a heap to the next-to-last position in the range and then forms a new heap from the remaining elements.
prev_permutation Reorders the elements in a range so that the original ordering is replaced by the lexicographically next greater permutation if it exists, where the sense of next may be specified with a binary predicate.
push_heap Adds an element that is at the end of a range to an existing heap consisting of the prior elements in the range.
random_shuffle Rearranges a sequence of N elements in a range into one of N! possible arrangements selected at random.
remove Eliminates a specified value from a given range without disturbing the order of the remaining elements and returning the end of a new range free of the specified value.
remove_copy Copies elements from a source range to a destination range, except that elements of a specified value are not copied, without disturbing the order of the remaining elements and returning the end of a new destination range.
remove_copy_if Copies elements from a source range to a destination range, except that satisfying a predicate are not copied, without disturbing the order of the remaining elements and returning the end of a new destination range.
remove_if Eliminates elements that satisfy a predicate from a given range without disturbing the order of the remaining elements and returning the end of a new range free of the specified value.
replace Examines each element in a range and replaces it if it matches a specified value.
replace_copy Examines each element in a source range and replaces it if it matches a specified value while copying the result into a new destination range.
replace_copy_if Examines each element in a source range and replaces it if it satisfies a specified predicate while copying the result into a new destination range.
replace_if Examines each element in a range and replaces it if it satisfies a specified predicate.
reverse Reverses the order of the elements within a range.
reverse_copy Reverses the order of the elements within a source range while copying them into a destination range
rotate Exchanges the elements in two adjacent ranges.
rotate_copy Exchanges the elements in two adjacent ranges within a source range and copies the result to a destination range.
search Searches for the first occurrence of a sequence within a target range whose elements are equal to those in a given sequence of elements or whose elements are equivalent in a sense specified by a binary predicate to the elements in the given sequence.
search_n Searches for the first subsequence in a range that of a specified number of elements having a particular value or a relation to that value as specified by a binary predicate.
set_difference Unites all of the elements that belong to one sorted source range, but not to a second sorted source range, into a single, sorted destination range, where the ordering criterion may be specified by a binary predicate.
set_intersection Unites all of the elements that belong to both sorted source ranges into a single, sorted destination range, where the ordering criterion may be specified by a binary predicate.
set_symmetric_difference Unites all of the elements that belong to one, but not both, of the sorted source ranges into a single, sorted destination range, where the ordering criterion may be specified by a binary predicate.
set_union Unites all of the elements that belong to at least one of two sorted source ranges into a single, sorted destination range, where the ordering criterion may be specified by a binary predicate.
sort Arranges the elements in a specified range into a nondescending order or according to an ordering criterion specified by a binary predicate.
shuffle Shuffles (rearranges) elements for a given range using a random number generator.
sort_heap Converts a heap into a sorted range.
stable_partition Classifies elements in a range into two disjoint sets, with those elements satisfying a unary predicate preceding those that fail to satisfy it, preserving the relative order of equivalent elements.
stable_sort Arranges the elements in a specified range into a nondescending order or according to an ordering criterion specified by a binary predicate and preserves the relative ordering of equivalent elements.
swap Exchanges the values of the elements between two types of objects, assigning the contents of the first object to the second object and the contents of the second to the first.
swap_ranges Exchanges the elements of one range with the elements of another, equal sized range.
transform Applies a specified function object to each element in a source range or to a pair of elements from two source ranges and copies the return values of the function object into a destination range.
unique Removes duplicate elements that are adjacent to each other in a specified range.
unique_copy Copies elements from a source range into a destination range except for the duplicate elements that are adjacent to each other.
upper_bound Finds the position of the first element in an ordered range that has a value that is greater than a specified value, where the ordering criterion may be specified by a binary predicate.

See also

Header Files Reference
Thread Safety in the C++ Standard Library
C++ Standard Library Reference