Namespaces
Variants
Views
Actions

Difference between revisions of "cpp/algorithm/set difference"

From cppreference.com
< cpp‎ | algorithm
m (~ harmonization)
(Uses {{mark constexpr since c++20}}.)
 
(13 intermediate revisions by 4 users not shown)
Line 2: Line 2:
 
{{cpp/algorithm/navbar}}
 
{{cpp/algorithm/navbar}}
 
{{dcl begin}}
 
{{dcl begin}}
−
{{dcl header | algorithm}}
+
{{dcl header|algorithm}}
−
{{dcl rev multi | num=1 | since1= | until1=c++20 |dcl1=
+
{{dcla|num=1|notes={{mark constexpr since c++20}}|
 
template< class InputIt1, class InputIt2, class OutputIt >
 
template< class InputIt1, class InputIt2, class OutputIt >
 
OutputIt set_difference( InputIt1 first1, InputIt1 last1,
 
OutputIt set_difference( InputIt1 first1, InputIt1 last1,
 
                         InputIt2 first2, InputIt2 last2,
 
                         InputIt2 first2, InputIt2 last2,
 
                         OutputIt d_first );
 
                         OutputIt d_first );
−
|dcl2=
 
−
template< class InputIt1, class InputIt2, class OutputIt >
 
−
constexpr OutputIt set_difference( InputIt1 first1, InputIt1 last1,
 
−
                                  InputIt2 first2, InputIt2 last2,
 
−
                                  OutputIt d_first );
 
 
}}
 
}}
−
{{dcl | since=c++17 | until= | num=2 |1=
+
{{dcl|num=2|since=c++17|
−
template< class ExecutionPolicy, class ForwardIt1, class ForwardIt2, class ForwardIt3 >
+
template< class ExecutionPolicy,
−
ForwardIt3 set_difference( ExecutionPolicy&& policy, ForwardIt1 first1, ForwardIt1 last1,
+
          class ForwardIt1, class ForwardIt2, class ForwardIt3 >
 +
ForwardIt3 set_difference( ExecutionPolicy&& policy,
 +
                          ForwardIt1 first1, ForwardIt1 last1,
 
                           ForwardIt2 first2, ForwardIt2 last2,
 
                           ForwardIt2 first2, ForwardIt2 last2,
 
                           ForwardIt3 d_first );
 
                           ForwardIt3 d_first );
 
}}
 
}}
−
{{dcl rev multi | num=3 | since1= | until1=c++20 |dcl1=
+
{{dcla|num=3|notes={{mark constexpr since c++20}}|
 
template< class InputIt1, class InputIt2,
 
template< class InputIt1, class InputIt2,
 
           class OutputIt, class Compare >
 
           class OutputIt, class Compare >
Line 26: Line 23:
 
                         InputIt2 first2, InputIt2 last2,
 
                         InputIt2 first2, InputIt2 last2,
 
                         OutputIt d_first, Compare comp );
 
                         OutputIt d_first, Compare comp );
−
|dcl2=
 
−
template< class InputIt1, class InputIt2,
 
−
          class OutputIt, class Compare >
 
−
constexpr OutputIt set_difference( InputIt1 first1, InputIt1 last1,
 
−
                                  InputIt2 first2, InputIt2 last2,
 
−
                                  OutputIt d_first, Compare comp );
 
 
}}
 
}}
−
{{dcl | since=c++17 | until= | num=4 |1=
+
{{dcl|num=4|since=c++17|
−
template< class ExecutionPolicy, class ForwardIt1, class ForwardIt2,
+
template< class ExecutionPolicy,
 +
          class ForwardIt1, class ForwardIt2,
 
           class ForwardIt3, class Compare >
 
           class ForwardIt3, class Compare >
−
ForwardIt3 set_difference( ExecutionPolicy&& policy, ForwardIt1 first1, ForwardIt1 last1,
+
ForwardIt3 set_difference( ExecutionPolicy&& policy,
 +
                          ForwardIt1 first1, ForwardIt1 last1,
 
                           ForwardIt2 first2, ForwardIt2 last2,
 
                           ForwardIt2 first2, ForwardIt2 last2,
 
                           ForwardIt3 d_first, Compare comp );
 
                           ForwardIt3 d_first, Compare comp );
Line 42: Line 35:
 
{{dcl end}}
 
{{dcl end}}
  
−
Copies the elements from the sorted range {{tt|[first1, last1)}} which are not found in the sorted range {{tt|[first2, last2)}} to the range beginning at {{tt|d_first}}.  
+
Copies the elements from the sorted range {{range|first1|last1}} which are not found in the sorted range {{range|first2|last2}} to the range beginning at {{c|d_first}}. The output range is also sorted.
  
−
The resulting range is also sorted. Equivalent elements are treated individually, that is, if some element is found {{tt|m}} times in {{tt|[first1, last1)}} and {{tt|n}} times in {{tt|[first2, last2)}}, it will be copied to {{tt|d_first}} exactly {{c|std::max(m-n, 0)}} times. The resulting range cannot overlap with either of the input ranges.
+
If {{range|first1|last1}} contains {{c|m}} elements that are equivalent to each other and {{range|first2|last2}} contains {{c|n}} elements that are equivalent to them, the final {{c|std::max(m - n, 0)}} elements will be copied from {{range|first1|last1}} to the output range, preserving order.
  
−
@1@ Elements are compared using {{tt|operator<}} and the ranges must be sorted with respect to the same.
+
@1@ If {{range|first1|last1}} or {{range|first2|last2}} is not {{rlp|/#Requirements|sorted}} with respect to {{rev inl|until=c++20|{{c/core|operator<}}}}{{rev inl|since=c++20|{{c|std::less{}<!---->}}}}, the behavior is undefined.
−
@3@ Elements are compared using the given binary comparison function {{tt|comp}} and the ranges must be sorted with respect to the same.
+
 
−
@2,4@ Same as {{v|1,3}}, but executed according to {{tt|policy}}. {{cpp/algorithm/parallel overload precondition|plural=true}}
+
@3@ If {{range|first1|last1}} or {{range|first2|last2}} is not sorted with respect to {{c|comp}}, the behavior is undefined.
 +
 
 +
@2,4@ Same as {{v|1,3}}, but executed according to {{c|policy}}.
 +
@@ {{cpp/algorithm/parallel overload precondition|plural=yes}}
 +
 
 +
If the output range overlaps with {{range|first1|last1}} or {{range|first2|last2}}, the behavior is undefined.
  
 
===Parameters===
 
===Parameters===
 
{{par begin}}
 
{{par begin}}
−
{{par | first1, last1 | the range of elements to examine}}
+
{{par|first1, last1|the range of elements to examine}}
−
{{par | first2, last2 | the range of elements to search for}}
+
{{par|first2, last2|the range of elements to search for}}
−
{{par | d_first | the beginning of the destination range}}
+
{{par|d_first|the beginning of the output range}}
 
{{par exec pol}}
 
{{par exec pol}}
−
{{par cmp ord | comp | p1=InputIt1 | p2=InputIt2}}  
+
{{par cmp ord|comp|p1=InputIt1|p2=InputIt2}}  
 
{{par hreq}}
 
{{par hreq}}
−
{{par req named | InputIt1, InputIt2 | InputIterator}}
+
{{par req named|InputIt1, InputIt2|InputIterator}}
−
{{par req named | OutputIt | OutputIterator}}
+
{{par req named|OutputIt|OutputIterator}}
−
{{par req named | ForwardIt1, ForwardIt2, ForwardIt3 | ForwardIterator}}
+
{{par req named|ForwardIt1, ForwardIt2, ForwardIt3|ForwardIterator}}
 +
{{par req named|Compare|Compare}}
 
{{par end}}
 
{{par end}}
  
Line 67: Line 66:
  
 
===Complexity===
 
===Complexity===
−
At most {{math|2&middot;(N<sub>1</sub>+N<sub>2</sub>-1)}} comparisons, where {{math|N<sub>1</sub>}} {{c|{{=}} std::distance(first1, last1)}} and {{math|N<sub>2</sub>}} {{c|{{=}} std::distance(first2, last2)}}.
+
Given {{mathjax-or|\(\scriptsize N_1\)|N{{su|b=1}}}} as {{c|std::distance(first1, last1)}} and {{mathjax-or|\(\scriptsize N_2\)|N{{su|b=2}}}} as {{c|std::distance(first2, last2)}}:
 +
 
 +
@1,2@ At most {{mathjax-or|\(\scriptsize 2 \cdot (N_1+N_2)-1\)|2⋅(N{{su|b=1}}+N{{su|b=2}})-1}} comparisons using {{rev inl|until=c++20|{{c/core|operator<}}}}{{rev inl|since=c++20|{{c|std::less{}<!---->}}}}.
 +
 
 +
@3,4@ At most {{mathjax-or|\(\scriptsize 2 \cdot (N_1+N_2)-1\)|2⋅(N{{su|b=1}}+N{{su|b=2}})-1}} applications of the comparison function {{c|comp}}.
  
 
===Exceptions===
 
===Exceptions===
−
{{cpp/algorithm/parallel_exceptions_reporting_behavior|singular=no}}
+
{{cpp/algorithm/parallel exceptions reporting behavior|singular=no}}
  
 
===Possible implementation===
 
===Possible implementation===
−
{{eq fun
+
{{eq impl
−
| 1=
+
|title1=set_difference (1)|ver1=1|1=
 
template<class InputIt1, class InputIt2, class OutputIt>
 
template<class InputIt1, class InputIt2, class OutputIt>
 
OutputIt set_difference(InputIt1 first1, InputIt1 last1,
 
OutputIt set_difference(InputIt1 first1, InputIt1 last1,
−
                         InputIt2 first2, InputIt2 last2,
+
                         InputIt2 first2, InputIt2 last2, OutputIt d_first)
−
                        OutputIt d_first)
+
 
{
 
{
−
     while (first1 != last1) {
+
     while (first1 != last1)
−
         if (first2 == last2) return std::copy(first1, last1, d_first);
+
    {
−
 
+
         if (first2 == last2)
−
         if (*first1 < *first2) {
+
            return std::copy(first1, last1, d_first);
 +
       
 +
         if (*first1 < *first2)
 
             *d_first++ = *first1++;
 
             *d_first++ = *first1++;
−
         } else {
+
         else
−
             if (! (*first2 < *first1)) {
+
        {
 +
             if (! (*first2 < *first1))
 
                 ++first1;
 
                 ++first1;
−
            }
 
 
             ++first2;
 
             ++first2;
 
         }
 
         }
Line 94: Line 98:
 
     return d_first;
 
     return d_first;
 
}
 
}
−
| 2=
+
|title2=set_difference (3)|ver2=3|2=
−
template<class InputIt1, class InputIt2,
+
template<class InputIt1, class InputIt2, class OutputIt, class Compare>
−
        class OutputIt, class Compare>
+
OutputIt set_difference(InputIt1 first1, InputIt1 last1,
−
OutputIt set_difference( InputIt1 first1, InputIt1 last1,
+
                        InputIt2 first2, InputIt2 last2, OutputIt d_first, Compare comp)
−
                        InputIt2 first2, InputIt2 last2,
+
−
                        OutputIt d_first, Compare comp)
+
 
{
 
{
−
     while (first1 != last1) {
+
     while (first1 != last1)
−
         if (first2 == last2) return std::copy(first1, last1, d_first);
+
    {
−
 
+
         if (first2 == last2)
−
         if (comp(*first1, *first2)) {
+
            return std::copy(first1, last1, d_first);
 +
       
 +
         if (comp(*first1, *first2))
 
             *d_first++ = *first1++;
 
             *d_first++ = *first1++;
−
         } else {
+
         else
−
             if (!comp(*first2, *first1)) {
+
        {
 +
             if (!comp(*first2, *first1))
 
                 ++first1;
 
                 ++first1;
−
            }
 
 
             ++first2;
 
             ++first2;
 
         }
 
         }
Line 119: Line 123:
 
===Example===
 
===Example===
 
{{example
 
{{example
−
|
+
|code=
−
| code=
+
 
#include <algorithm>
 
#include <algorithm>
 
#include <iostream>
 
#include <iostream>
Line 126: Line 129:
 
#include <vector>
 
#include <vector>
  
−
auto print = [](const auto& v, const char* end = "") {
+
template<typename T>
−
     std::cout << "{ ";
+
std::ostream& operator<<(std::ostream& os, const std::vector<T>& v)
−
     for (auto i : v) std::cout << i << ' ';
+
{
−
     std::cout << "} " << end;
+
     os << '{';
−
};
+
     for (auto n{v.size()}; const auto& e : v)
 +
        os << e << (--n ? ", " : "");
 +
     return os << '}';
 +
}
  
−
struct Order // a struct with some interesting data
+
struct Order // a struct with very interesting data
 
{
 
{
−
     int order_id;
+
     int order_id{};
 +
   
 +
    friend std::ostream& operator<<(std::ostream& os, const Order& ord)
 +
    {
 +
        return os << ord.order_id;
 +
    }
 
};
 
};
  
−
std::ostream& operator<<(std::ostream& os, const Order& ord)
+
int main()
 
{
 
{
−
    return os << ord.order_id << ',';
+
     const std::vector<int> v1{1, 2, 5, 5, 5, 9};
−
}
+
     const std::vector<int> v2{2, 5, 7};
−
 
+
−
int main() {
+
−
     const std::vector<int> v1 {1, 2, 5, 5, 5, 9};
+
−
     const std::vector<int> v2 {2, 5, 7};
+
 
     std::vector<int> diff;
 
     std::vector<int> diff;
−
 
+
   
 
     std::set_difference(v1.begin(), v1.end(), v2.begin(), v2.end(),
 
     std::set_difference(v1.begin(), v1.end(), v2.begin(), v2.end(),
 
                         std::inserter(diff, diff.begin()));
 
                         std::inserter(diff, diff.begin()));
−
     print(v1, "∖ ");
+
      
−
    print(v2, "= ");
+
    std::cout << v1 << " ∖ " << v2 << " == " << diff << "\n\n";
−
    print(diff, "\n");
+
   
−
 
+
 
     // we want to know which orders "cut" between old and new states:
 
     // we want to know which orders "cut" between old and new states:
−
     std::vector<Order> old_orders { {1}, {2}, {5}, {9} };
+
     std::vector<Order> old_orders{<!---->{1}, {2}, {5}, {9}<!---->};
−
     std::vector<Order> new_orders { {2}, {5}, {7} };
+
     std::vector<Order> new_orders{<!---->{2}, {5}, {7}<!---->};
 
     std::vector<Order> cut_orders;
 
     std::vector<Order> cut_orders;
−
 
+
   
 
     std::set_difference(old_orders.begin(), old_orders.end(),
 
     std::set_difference(old_orders.begin(), old_orders.end(),
 
                         new_orders.begin(), new_orders.end(),
 
                         new_orders.begin(), new_orders.end(),
 
                         std::back_inserter(cut_orders),
 
                         std::back_inserter(cut_orders),
 
                         [](auto& a, auto& b) { return a.order_id < b.order_id; });
 
                         [](auto& a, auto& b) { return a.order_id < b.order_id; });
 +
   
 +
    std::cout << "old orders: " << old_orders << '\n'
 +
              << "new orders: " << new_orders << '\n'
 +
              << "cut orders: " << cut_orders << '\n';
 +
}
 +
|output=
 +
{1, 2, 5, 5, 5, 9} ∖ {2, 5, 7} == {1, 5, 5, 9}
  
−
    std::cout << "old orders = "; print(old_orders, "\n");
+
old orders: {1, 2, 5, 9}
−
    std::cout << "new orders = "; print(new_orders, "\n");
+
new orders: {2, 5, 7}
−
    std::cout << "cut orders = "; print(cut_orders, "\n");
+
cut orders: {1, 9}
−
}
+
−
| output=
+
−
{ 1 2 5 5 5 9 } ∖ { 2 5 7 } = { 1 5 5 9 }
+
−
old orders = { 1, 2, 5, 9, }  
+
−
new orders = { 2, 5, 7, }  
+
−
cut orders = { 1, 9, }
+
 
}}
 
}}
 +
 +
===Defect reports===
 +
{{dr list begin}}
 +
{{dr list item|wg=lwg|dr=291|std=C++98|before=it was unspecified how to handle equivalent elements in the input ranges|after=specified}}
 +
{{dr list end}}
  
 
===See also===
 
===See also===
 
{{dsc begin}}
 
{{dsc begin}}
−
{{dsc inc | cpp/algorithm/dsc includes}}
+
{{dsc inc|cpp/algorithm/dsc includes}}
−
{{dsc inc | cpp/algorithm/dsc set_symmetric_difference}}
+
{{dsc inc|cpp/algorithm/dsc set_symmetric_difference}}
 +
{{dsc inc|cpp/algorithm/ranges/dsc set_difference}}
 
{{dsc end}}
 
{{dsc end}}
  
 
{{langlinks|de|es|fr|it|ja|pt|ru|zh}}
 
{{langlinks|de|es|fr|it|ja|pt|ru|zh}}

Latest revision as of 00:00, 7 April 2024

 
C++
 
Algorithm library
Constrained algorithms and algorithms on ranges (C++20)
Constrained algorithms, e.g. ranges::copy, ranges::sort, ...
Execution policies (C++17)
Non-modifying sequence operations
Batch operations
(C++17)
Search operations
(C++11)                (C++11)(C++11)

Modifying sequence operations
Copy operations
(C++11)
(C++11)
(C++11)
Swap operations
Transformation operations
Generation operations
Removing operations
Order-changing operations
(until C++17)(C++11)
(C++20)(C++20)
Sampling operations
(C++17)

Sorting and related operations
Partitioning operations
Sorting operations
Binary search operations
(on partitioned ranges)
Set operations (on sorted ranges)
set_difference

Merge operations (on sorted ranges)
Heap operations
Minimum/maximum operations
(C++11)
(C++17)
Lexicographical comparison operations
(C++20)
Permutation operations
C library
Numeric operations
Operations on uninitialized memory
 
Defined in header <algorithm>
template< class InputIt1, class InputIt2, class OutputIt >

OutputIt set_difference( InputIt1 first1, InputIt1 last1,
                         InputIt2 first2, InputIt2 last2,

                         OutputIt d_first );
 (1) (constexpr since C++20)
template< class ExecutionPolicy,

          class ForwardIt1, class ForwardIt2, class ForwardIt3 >
ForwardIt3 set_difference( ExecutionPolicy&& policy,
                           ForwardIt1 first1, ForwardIt1 last1,
                           ForwardIt2 first2, ForwardIt2 last2,

                           ForwardIt3 d_first );
 (2) (since C++17)
template< class InputIt1, class InputIt2,

          class OutputIt, class Compare >
OutputIt set_difference( InputIt1 first1, InputIt1 last1,
                         InputIt2 first2, InputIt2 last2,

                         OutputIt d_first, Compare comp );
 (3) (constexpr since C++20)
template< class ExecutionPolicy,

          class ForwardIt1, class ForwardIt2,
          class ForwardIt3, class Compare >
ForwardIt3 set_difference( ExecutionPolicy&& policy,
                           ForwardIt1 first1, ForwardIt1 last1,
                           ForwardIt2 first2, ForwardIt2 last2,

                           ForwardIt3 d_first, Compare comp );
 (4) (since C++17)

Copies the elements from the sorted range [first1, last1) which are not found in the sorted range [first2, last2) to the range beginning at d_first. The output range is also sorted.

If [first1, last1) contains m elements that are equivalent to each other and [first2, last2) contains n elements that are equivalent to them, the final std::max(m - n, 0) elements will be copied from [first1, last1) to the output range, preserving order.

1) If [first1, last1) or [first2, last2) is not sorted with respect to operator<(until C++20)std::less{}(since C++20), the behavior is undefined.
3) If [first1, last1) or [first2, last2) is not sorted with respect to comp, the behavior is undefined.
2,4) Same as (1,3), but executed according to policy.
These overloads participate in overload resolution only if

std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true.

(until C++20)

std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>> is true.

(since C++20)

If the output range overlaps with [first1, last1) or [first2, last2), the behavior is undefined.

Contents

[edit] Parameters

first1, last1 - the range of elements to examine
first2, last2 - the range of elements to search for
d_first - the beginning of the output range
policy - the execution policy to use. See execution policy for details.
comp - comparison function object (i.e. an object that satisfies the requirements of Compare) which returns ​true if the first argument is less than (i.e. is ordered before) the second.

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 objects of types InputIt1 and InputIt2 can be dereferenced and then implicitly converted to both Type1 and Type2. ​

Type requirements
-
InputIt1, InputIt2 must meet the requirements of LegacyInputIterator.
-
OutputIt must meet the requirements of LegacyOutputIterator.
-
ForwardIt1, ForwardIt2, ForwardIt3 must meet the requirements of LegacyForwardIterator.
-
Compare must meet the requirements of Compare.

[edit] Return value

Iterator past the end of the constructed range.

[edit] Complexity

Given N1 as std::distance(first1, last1) and N2 as std::distance(first2, last2):

1,2) At most 2⋅(N1+N2)-1 comparisons using operator<(until C++20)std::less{}(since C++20).
3,4) At most 2⋅(N1+N2)-1 applications of the comparison function comp.

[edit] 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 standard policies, std::terminate is called. For any other ExecutionPolicy, the behavior is implementation-defined.
  • If the algorithm fails to allocate memory, std::bad_alloc is thrown.

[edit] Possible implementation

set_difference (1) 
template<class InputIt1, class InputIt2, class OutputIt>
OutputIt set_difference(InputIt1 first1, InputIt1 last1,
                        InputIt2 first2, InputIt2 last2, OutputIt d_first)
{
    while (first1 != last1)
    {
        if (first2 == last2)
            return std::copy(first1, last1, d_first);
 
        if (*first1 < *first2)
            *d_first++ = *first1++;
        else
        {
            if (! (*first2 < *first1))
                ++first1;
            ++first2;
        }
    }
    return d_first;
}
set_difference (3) 
template<class InputIt1, class InputIt2, class OutputIt, class Compare>
OutputIt set_difference(InputIt1 first1, InputIt1 last1,
                        InputIt2 first2, InputIt2 last2, OutputIt d_first, Compare comp)
{
    while (first1 != last1)
    {
        if (first2 == last2)
            return std::copy(first1, last1, d_first);
 
        if (comp(*first1, *first2))
            *d_first++ = *first1++;
        else
        {
            if (!comp(*first2, *first1))
                ++first1;
            ++first2;
        }
    }
    return d_first;
}

[edit] Example

Run this code
#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>
 
template<typename T>
std::ostream& operator<<(std::ostream& os, const std::vector<T>& v)
{
    os << '{';
    for (auto n{v.size()}; const auto& e : v)
        os << e << (--n ? ", " : "");
    return os << '}';
}
 
struct Order // a struct with very interesting data
{
    int order_id{};
 
    friend std::ostream& operator<<(std::ostream& os, const Order& ord)
    {
        return os << ord.order_id;
    }
};
 
int main()
{
    const std::vector<int> v1{1, 2, 5, 5, 5, 9};
    const std::vector<int> v2{2, 5, 7};
    std::vector<int> diff;
 
    std::set_difference(v1.begin(), v1.end(), v2.begin(), v2.end(),
                        std::inserter(diff, diff.begin()));
 
    std::cout << v1 << " ∖ " << v2 << " == " << diff << "\n\n";
 
    // we want to know which orders "cut" between old and new states:
    std::vector<Order> old_orders{{1}, {2}, {5}, {9}};
    std::vector<Order> new_orders{{2}, {5}, {7}};
    std::vector<Order> cut_orders;
 
    std::set_difference(old_orders.begin(), old_orders.end(),
                        new_orders.begin(), new_orders.end(),
                        std::back_inserter(cut_orders),
                        [](auto& a, auto& b) { return a.order_id < b.order_id; });
 
    std::cout << "old orders: " << old_orders << '\n'
              << "new orders: " << new_orders << '\n'
              << "cut orders: " << cut_orders << '\n';
}

Output: 

{1, 2, 5, 5, 5, 9} ∖ {2, 5, 7} == {1, 5, 5, 9}
 
old orders: {1, 2, 5, 9}
new orders: {2, 5, 7}
cut orders: {1, 9}

[edit] 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 291 C++98 it was unspecified how to handle equivalent elements in the input ranges specified

[edit] See also

 returns true if one sequence is a subsequence of another
(function template) [edit]
computes the symmetric difference between two sets
(function template) [edit]
(C++20)
 computes the difference between two sets
(niebloid)[edit]
Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/algorithm/set_difference&oldid=170685"