std::minmax

 

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Template:ddcl list begin <tr class="t-dsc-header">

<td>

Defined in header <algorithm>

</td>

<td></td> <td></td> </tr> <tr class="t-dcl ">

<td >

template< class T >
std::pair<const T&,const T&> minmax( const T& a, const T& b );

</td>

<td > (1) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

<td >

template< class T, class Compare >
std::pair<const T&,const T&> minmax( const T& a, const T& b, Compare comp );

</td>

<td > (2) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

<td >

template< class T >
std::pair<T,T> minmax( std::initializer_list<T> ilist);

</td>

<td > (3) </td> <td > (since C++11) </td> </tr> <tr class="t-dcl ">

<td >

template< class T, class Compare >
std::pair<T,T> minmax( std::initializer_list<T> ilist, Compare comp );

</td>

<td > (4) </td> <td > (since C++11) </td> </tr> Template:ddcl list end

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 object (i.e. an object that satisfies the requirements of Compare) 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); 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. 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

Template:cpp/algorithm/dcl list minTemplate:cpp/algorithm/dcl list max