std::minmax

 

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Algorithm library

Functions
Non-modifying sequence operations
all_of any_of none_of (C++11) (C++11) (C++11) for_each count count_if mismatch equal	find find_if find_if_not (C++11) find_end find_first_of adjacent_find search search_n
Modifying sequence operations
copy copy_if (C++11) copy_n (C++11) copy_backward move (C++11) move_backward (C++11) fill fill_n transform generate generate_n remove remove_if remove_copy remove_copy_if	replace replace_if replace_copy replace_copy_if swap swap_ranges iter_swap reverse reverse_copy rotate rotate_copy random_shuffle shuffle   (C++11) unique unique_copy
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is_partitioned (C++11) partition partition_copy (C++11)	stable_partition partition_point (C++11)
Sorting operations (on sorted ranges)
is_sorted (C++11) is_sorted_until (C++11) sort	partial_sort partial_sort_copy stable_sort nth_element
Binary search operations (on sorted ranges)
lower_bound upper_bound	binary_search equal_range
Set operations (on sorted ranges)
merge inplace_merge includes	set_difference set_intersection set_symmetric_difference set_union
Heap operations
is_heap is_heap_until (C++11) make_heap	push_heap pop_heap sort_heap
Minimum/maximum operations
max max_element min min_element minmax (C++11) minmax_element (C++11)	lexicographical_compare is_permutation (C++11) next_permutation prev_permutation
Numeric operations
iota (C++11) accumulate inner_product	adjacent_difference partial_sum
C library
qsort	bsearch

 

Defined in header <algorithm>
template< class T > std::pair<const T&,const T&> minmax( const T& a, const T& b );	(1)	(since C++11)
template< class T, class Compare > std::pair<const T&,const T&> minmax( const T& a, const T& b, Compare comp );	(2)	(since C++11)
template< class T > std::pair<T,T> minmax( std::initializer_list<T> ilist);	(3)	(since C++11)
template< class T, class Compare > std::pair<T,T> minmax( std::initializer_list<T> ilist, Compare comp );	(4)	(since C++11)

1-2) Returns the smaller and the greater of the two values.

3-4) Returns the smallest and the greatest of the values in initializer list ilist.

The (1,3) versions use operator< to compare the values, whereas the (2,4) versions use the given comparison function comp.

Parameters

a, b	-	the values to compare
ilist	-	initializer list with the values to compare
comp	-	comparison function which returns ​true if if a is less than b. The signature of the comparison function should be equivalent to the following: bool cmp(const Type1 &a, const Type2 &b); The signature does not need to have const &, but the function must not modify the objects passed to it. The types Type1 and Type2 must be such that an object of type T can be implicitly converted to both of them. ​
Type requirements
- T must meet the requirements of LessThanComparable. for the overloads (1) and (3)
- T must meet the requirements of CopyConstructible. for the overloads (3) and (4)

Return value

1-2) Returns the result of std::make_pair(a, b) if a<b or if a is equivalent to b. Returns the result of std::make_pair(b, a) if b<a.

3-4) A pair with the smallest value in ilist as the first element and the greatest as the second. If several elements are equivalent to the smallest, the leftmost such element is returned. If several elements are equivalent to the largest, the rightmost such element is returned.

Complexity

1-2) Constant

3-4) Linear in ilist.size()

Possible implementation

First version
template<class T> std::pair<const T&,const T&> minmax(const T& a, const T& b) { return (b < a) ? std::make_pair(b, a) : std::make_pair(a, b); }
Second version
template<class T, class Compare> std::pair<const T&,const T&> minmax(const T& a, const T& b, Compare comp) { return comp(b, a) ? std::make_pair(b, a) : std::make_pair(a, b); }
Third version
template< class T > std::pair<T,T> minmax( std::initializer_list ilist) { auto p = std::minmax_element(ilist.begin(), ilist.end()); return std::make_pair(*p.first, *p.second); }
Fourth version
template< class T, class Compare > std::pair<T,T> minmax( std::initializer_list ilist, Compare comp ) { auto p = std::minmax_element(ilist.begin(), ilist.end(), comp); return std::make_pair(*p.first, *p.second); }

Example

run this code

#include <algorithm>
#include <iostream>
#include <vector>
#include <cstdlib>
#include <ctime>
 
int main()
{
    std::vector<int> v {3, 1, 4, 1, 5, 9, 2, 6}; 
    std::srand(std::time(0));
    std::pair<int,int> bounds = std::minmax(std::rand() % v.size(),
                                            std::rand() % v.size());
 
    std::cout << "v[" << bounds.first << "," << bounds.second << "]: ";
    for (int i = bounds.first; i < bounds.second; ++i) {
        std::cout << v[i] << ' ';
    }
    std::cout << '\n';
}

Possible output:

v[2,7]: 4 1 5 9 2

See also

min	returns the smaller of two elements (function template)
max	returns the larger of two elements (function template)