std::min

 

C++

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Algorithm library

Constrained algorithms and algorithms on ranges (C++20)
Constrained algorithms, e.g. ranges::copy, ranges::sort, ...
Execution policies (C++17)
is_execution_policy (C++17)	execution::seqexecution::parexecution::par_unseqexecution::unseq (C++17)(C++17)(C++17)(C++20)	execution::sequenced_policyexecution::parallel_policyexecution::parallel_unsequenced_policyexecution::parallel_unsequenced (C++17)(C++17)(C++17)(C++20)
Non-modifying sequence operations
all_ofany_ofnone_of (C++11)(C++11)(C++11) for_each for_each_n (C++17)	countcount_if mismatch equal adjacent_find	search search_n lexicographical_compare lexicographical_compare_three_way (C++20)	findfind_iffind_if_not (C++11) find_end find_first_of
Modifying sequence operations
copycopy_if (C++11) copy_n (C++11) copy_backward move (C++11) move_backward (C++11) shift_leftshift_right (C++20)(C++20) transform	fill fill_n generate generate_n swap iter_swap swap_ranges sample (C++17)	removeremove_if replacereplace_if reverse rotate unique random_shuffle (until C++17)	remove_copyremove_copy_if replace_copyreplace_copy_if reverse_copy rotate_copy unique_copy shuffle (C++11)
Partitioning operations
is_partitioned (C++11) partition_point (C++11)	partition partition_copy (C++11)	stable_partition
Sorting operations
is_sorted (C++11) is_sorted_until (C++11)	sort stable_sort	partial_sort partial_sort_copy	nth_element
Binary search operations
lower_bound	upper_bound	binary_search	equal_range
Set operations (on sorted ranges)
merge inplace_merge	set_difference set_intersection	set_symmetric_difference set_union	includes
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is_heap (C++11) is_heap_until (C++11)	make_heap sort_heap	push_heap pop_heap
Minimum/maximum operations
max max_element	min min_element	minmax (C++11) minmax_element (C++11)	clamp (C++17)
Permutations
is_permutation (C++11)	next_permutation	prev_permutation
Numeric operations
iota (C++11) inner_product adjacent_difference	accumulate reduce (C++17) transform_reduce (C++17)	transform_inclusive_scan (C++17) transform_exclusive_scan (C++17)	partial_sum inclusive_scan (C++17) exclusive_scan (C++17)
Operations on uninitialized storage
uninitialized_copy uninitialized_move (C++17) uninitialized_fill	uninitialized_copy_n (C++11) uninitialized_move_n (C++17) uninitialized_fill_n	uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) uninitialized_default_construct_n (C++17) uninitialized_value_construct_n (C++17)	destroy (C++17) destroy_n (C++17) destroy_at (C++17) construct_at (C++20)
C library
qsort	bsearch

 

Defined in header <algorithm>
	(1)
template< class T > const T& min( const T& a, const T& b );			(until C++14)
template< class T > constexpr const T& min( const T& a, const T& b );			(since C++14)
		(2)
template< class T, class Compare > const T& min( const T& a, const T& b, Compare comp );				(until C++14)
template< class T, class Compare > constexpr const T& min( const T& a, const T& b, Compare comp );				(since C++14)
			(3)
template< class T > T min( std::initializer_list<T> ilist );					(since C++11) (until C++14)
template< class T > constexpr T min( std::initializer_list<T> ilist );					(since C++14)
				(4)
template< class T, class Compare > T min( std::initializer_list<T> ilist, Compare comp );						(since C++11) (until C++14)
template< class T, class Compare > constexpr T min( std::initializer_list<T> ilist, Compare comp );						(since C++14)

Returns the smaller of the given values.

1-2) Returns the smaller of a and b.

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

The (1,3) versions use operator< to compare the values, 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
cmp	-	comparison function object (i.e. an object that satisfies the requirements of Compare) which returns ​true 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); While the signature does not need to have const &, the function must not modify the objects passed to it and must be able to accept all values of type (possibly const) Type1 and Type2 regardless of value category (thus, Type1 & is not allowed, nor is Type1 unless for Type1 a move is equivalent to a copy (since C++11)). 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 in order to use overloads (1,3).
- T must meet the requirements of CopyConstructible in order to use overloads (3,4).

Return value

1-2) The smaller of a and b. If the values are equivalent, returns a.

3-4) The smallest value in ilist. If several values are equivalent to the smallest, returns the leftmost such value.

Complexity

1-2) Exactly one comparison

3-4) Exactly ilist.size() - 1 comparisons

Possible implementation

First version
template<class T> const T& min(const T& a, const T& b) { return (b < a) ? b : a; }
Second version
template<class T, class Compare> const T& min(const T& a, const T& b, Compare comp) { return (comp(b, a)) ? b : a; }
Third version
template<class T> T min( std::initializer_list<T> ilist) { return *std::min_element(ilist.begin(), ilist.end()); }
Fourth version
template<class T, class Compare> T min(std::initializer_list<T> ilist, Compare comp) { return *std::min_element(ilist.begin(), ilist.end(), comp); }

Notes

Capturing the result of std::min by reference produces a dangling reference if one of the parameters is a temporary and that parameter is returned:

int n = 1;
const int& r = std::min(n-1, n+1);
// r is dangling

Example

Run this code

#include <algorithm>
#include <iostream>
#include <string_view>
 
int main()
{
    std::cout << "smaller of 1 and 9999 is " << std::min(1, 9999) << '\n'
              << "smaller of 'a', and 'b' is '" << std::min('a', 'b') << "'\n"
              << "shortest of \"foo\", \"bar\", and \"hello\" is \""
              << std::min({ "foo", "bar", "hello" },
                          [](const std::string_view s1, const std::string_view s2) {
                              return s1.size() < s2.size();
                          }) << "\"\n";
}

Output:

smaller of 1 and 9999 is 1
smaller of 'a', and 'b' is 'a'
shortest of "foo", "bar", and "hello" is "foo"

See also

max	returns the greater of the given values (function template)
minmax (C++11)	returns the smaller and larger of two elements (function template)
min_element	returns the smallest element in a range (function template)
clamp (C++17)	clamps a value between a pair of boundary values (function template)
ranges::min (C++20)	returns the smaller of the given values (niebloid)