From cppreference.com
Defined in header
template<classForwardIt>ForwardItmin_element(ForwardItfirst,ForwardItlast); (1)(constexpr since C++17)template<classExecutionPolicy,classForwardIt>ForwardItmin_element(ExecutionPolicy&&policy,ForwardItfirst,ForwardItlast); (2) (since C++17)template<classForwardIt,classCompare>ForwardItmin_element(ForwardItfirst,ForwardItlast,Comparecomp); (3)(constexpr since C++17)template<classExecutionPolicy,classForwardIt,classCompare>ForwardItmin_element(ExecutionPolicy&&policy,ForwardItfirst,ForwardItlast,Comparecomp); (4) (since C++17)Finds the smallest element in the range [first, last).
1) Elements are compared using operator<(until C++20)std::less{}(since C++20).
3) Elements are compared using the comparison function comp.
2,4) Same as (1,3), but executed according to policy.
These overloads participate in overload resolution only if the value of the following expression is true:
std::is_execution_policy_v<std::decay_t<ExecutionPolicy>>
(until C++20)std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>>
(since C++20)Parameters
first, last - the pair of iterators defining the
of elements to examine policy - the
to use comp - comparison function object (i.e. an object that satisfies the requirements of
) which returns true if the first argument is less than the second. The signature of the comparison function should be equivalent to the following:
boolcmp(constType1&a,constType2&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
(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 ForwardIt can be dereferenced and then implicitly converted to both of them.
Type requirements -ForwardIt must meet the requirements of
. Return value
Iterator to the smallest element in the range [first, last). If several elements in the range are equivalent to the smallest element, returns the iterator to the first such element. Returns last if the range is empty.
Complexity
Given N as std::distance(first,last):
1,2) Exactly max(N-1,0) comparisons using operator<(until C++20)std::less{}(since C++20).
3,4) Exactly max(N-1,0) applications of the comparison function comp.
Exceptions
The overloads with a template parameter named ExecutionPolicy report errors as follows:
If execution of a function invoked as part of the algorithm throws an exception and ExecutionPolicy is one of the
,
is called. For any other ExecutionPolicy, the behavior is implementation-defined.
If the algorithm fails to allocate memory,
is thrown.
Possible implementation
template<classForwardIt>ForwardItmin_element(ForwardItfirst,ForwardItlast){if(first==last)returnlast;ForwardItsmallest=first;while(++first!=last)if(*first<*smallest)smallest=first;returnsmallest;}
template<classForwardIt,classCompare>ForwardItmin_element(ForwardItfirst,ForwardItlast,Comparecomp){if(first==last)returnlast;ForwardItsmallest=first;while(++first!=last)if(comp(*first,*smallest))smallest=first;returnsmallest;}Example
Run this code
#include<algorithm>#include<iostream>#include<vector>intmain(){std::vector<int>v{3,1,-4,1,5,9};std::vector<int>::iteratorresult=std::min_element(v.begin(),v.end());std::cout<<"min element has value "<<*result<<" and index ["<<std::distance(v.begin(),result)<<"]\n";}Output:
min element has value -4 and index [2] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR Applied to Behavior as published Correct behavior
C++98 the return value was not specified if [first, last) is empty returns last in this case
C++98 the iterator to the first non-greatest element was returned corrected the return value See also
returns the largest element in a range
(function template & algorithm function object)
(C++20)
(C++11)
returns the smallest and the largest elements in a range
(function template & algorithm function object)
(C++20)
returns the smaller of the given values
(function template & algorithm function object)
(C++20)
(C++20)
returns the smallest element in a range
(algorithm function object)