list::unique (STL/CLR)

Article
06/05/2017

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The latest version of this topic can be found at list::unique (STL/CLR).

Removes adjacent elements that pass a specified test.

Syntax

void unique();  
template<typename Pred2>  
    void unique(Pred2 pred);

Parameters

pred
Comparer for element pairs.

Remarks

The first member function removes from the controlled sequence (erases) every element that compares equal to its preceding element -- if element X precedes element Y and X == Y, the member function removes Y. You use it to remove all but one copy of every subsequence of adjacent elements that compare equal. Note that if the controlled sequence is ordered, such as by calling list::sort (STL/CLR)(), the member function leaves only elements with unique values. (Hence the name).

The second member function behaves the same as the first, except that it removes each element Y following an element X for which pred``(X, Y). You use it to remove all but one copy of every subsequence of adjacent elements that satisfy a predicate function or delegate that you specify. Note that if the controlled sequence is ordered, such as by calling sort(``pred``), the member function leaves only elements that do not have equivalent ordering with any other elements.

Example

// cliext_list_unique.cpp   
// compile with: /clr   
#include <cliext/list>   
  
int main()   
    {   
    cliext::list<wchar_t> c1;   
    c1.push_back(L'a');   
    c1.push_back(L'a');   
    c1.push_back(L'b');   
    c1.push_back(L'c');   
  
// display initial contents " a a b c"   
    for each (wchar_t elem in c1)   
        System::Console::Write(" {0}", elem);   
    System::Console::WriteLine();   
  
// display contents after unique   
    cliext::list<wchar_t> c2(c1);   
    c2.unique();   
    for each (wchar_t elem in c2)   
        System::Console::Write(" {0}", elem);   
    System::Console::WriteLine();   
  
// display contents after unique(not_equal_to)   
    c2 = c1;   
    c2.unique(cliext::not_equal_to<wchar_t>());   
    for each (wchar_t elem in c2)   
        System::Console::Write(" {0}", elem);   
    System::Console::WriteLine();   
    return (0);   
    }

a a b c  
a b c  
a a

Requirements

Header: <cliext/list>

Namespace: cliext

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