std::min

 

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Constrained algorithms, e.g. ranges::copy, ranges::sort, ...
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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 Batch operations for_each for_each_n (C++17) Search operations all_ofany_ofnone_of (C++11)                (C++11)(C++11) countcount_if mismatch equal findfind_iffind_if_not (C++11) find_end find_first_of adjacent_find search search_n Modifying sequence operations Copy operations copycopy_if (C++11) copy_backward copy_n (C++11) move (C++11) move_backward (C++11) Swap operations swap iter_swap swap_ranges Transformation operations replacereplace_if transform replace_copyreplace_copy_if Generation operations fill fill_n generate generate_n Removing operations removeremove_if unique remove_copyremove_copy_if unique_copy Order-changing operations reverse reverse_copy rotate rotate_copy random_shuffleshuffle (until C++17)(C++11) shift_leftshift_right (C++20)(C++20) Sampling operations sample (C++17)	Sorting and related operations Partitioning operations partition partition_copy (C++11)   stable_partition is_partitioned (C++11) partition_point (C++11) Sorting operations sort stable_sort partial_sort partial_sort_copy is_sorted (C++11) is_sorted_until (C++11) nth_element Binary search operations (on partitioned ranges) lower_bound upper_bound equal_range binary_search Set operations (on sorted ranges) includes set_union set_intersection set_difference set_symmetric_difference Merge operations (on sorted ranges) merge inplace_merge Heap operations push_heap pop_heap make_heap sort_heap is_heap (C++11) is_heap_until (C++11) Minimum/maximum operations max min minmax (C++11) clamp (C++17) max_element min_element minmax_element (C++11) Lexicographical comparison operations lexicographical_compare lexicographical_compare_three_way (C++20) Permutation operations next_permutation prev_permutation is_permutation (C++11) C library qsort bsearch
Numeric operations
iota (C++11) inner_product adjacent_difference    accumulate reduce (C++17) transform_reduce (C++17)	partial_sum inclusive_scan (C++17)    exclusive_scan (C++17) transform_inclusive_scan (C++17) transform_exclusive_scan (C++17)
Operations on uninitialized memory
uninitialized_copy uninitialized_move (C++17)    uninitialized_fill uninitialized_copy_n (C++11) uninitialized_move_n (C++17) uninitialized_fill_n	destroy (C++17) destroy_n (C++17) destroy_at (C++17) construct_at (C++20)       uninitialized_default_construct (C++17) uninitialized_value_construct (C++17) uninitialized_default_construct_n (C++17) uninitialized_value_construct_n (C++17)

 

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

Returns the smaller of the given values.

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

1) Uses operator< to compare the values.

If T is not LessThanComparable, the behavior is undefined.

2) Use the comparison function comp to compare the values.

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

If ilist.size() is zero, or T is not CopyConstructible, the behavior is undefined.

3) Uses operator< to compare the values.

If T is not LessThanComparable, the behavior is undefined.

4) Use the comparison function comp to compare the values.

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.

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) Exactly one comparison using operator<.

2) Exactly one application of the comparison function comp.

3,4) Given \(\scriptsize N\)N as ilist.size():

3) Exactly \(\scriptsize N-1\)N-1 comparisons using operator<.

4) Exactly \(\scriptsize N-1\)N-1 applications of the comparison function comp.

Possible implementation

min (1)
template<class T> const T& min(const T& a, const T& b) { return (b < a) ? b : a; }
min (2)
template<class T, class Compare> const T& min(const T& a, const T& b, Compare comp) { return (comp(b, a)) ? b : a; }
min (3)
template<class T> T min(std::initializer_list<T> ilist) { return *std::min_element(ilist.begin(), ilist.end()); }
min (4)
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 + 2, n * 2); // r is dangling

Example

Run this code

#include <algorithm>
#include <iostream>
#include <string_view>
 
int main()
{
    std::cout << "smaller of 10 and 010 is " << std::min(10, 010) << '\n'
              << "smaller of 'd' and 'b' is '" << std::min('d', '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 10 and 010 is 8
smaller of 'd' and 'b' is 'b'
shortest of "foo", "bar", and "hello" is "foo"

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR	Applied to	Behavior as published	Correct behavior
LWG 281	C++98	T was required to be CopyConstructible for overloads (1,2)	not required

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)