std::unique

Removes all consecutive duplicate elements from the range [first, last)

eg.

int main(int argc, char* argv[])
{
   list<int> ivec1;

   for(list<int>::size_type i = 0;  i<10 ; ++i)
   {
       ivec1.push_back(i);
   }

   ivec1.push_back(9);

   cout<<"original content:"<<endl;
   for(list<int>::iterator i = ivec1.begin() ; i != ivec1.end() ; ++i)
   {
       cout<<*i<<endl;
   }

   vector<int> ivec;

   unique_copy(ivec1.begin(),ivec1.end(),back_inserter(ivec));

   cout<<"after unique_copy:"<<endl;
   for(vector<int>::iterator i = ivec.begin() ; i != ivec.end() ; ++i)
   {
       cout<<*i<<endl;
   }

   list<int>::iterator t = unique(ivec1.begin(),ivec1.end());
    cout<<"after unique:"<<endl;
   for(list<int>::iterator i = ivec1.begin() ; i != t ; ++i)
   {
       cout<<*i<<endl;
   }



   return 0;
}
 

當list 中元素是0,1,2,3,4,5,6,7,8,9,9時後面的輸出都是0,1,2,3,4,5,6,7,8,9;

但是當list 中元素是0,1,2,3,4,5,6,7,8,9,5後面的輸出都是0,1,2,3,4,5,6,7,8,9,5

結論

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unique 和其copy版本都只能"刪除"相鄰的重複元素