Use of the search_n() in CPP

[Garrick]

Hello, I am studying in the PQR college. I had just started to learn C++ language from the institute. I am interested in the programming and I had heard that the C++ language can be the very simple programming language. So, I would like to know about the search_n() function of the C++ language. Also, I would like to know about the use of the search_n() function in the C++ programming. Can anyone has the solution for me on the search_n() function. Reply Me!!!

[MindSpace]

Hi, To Search the given specified range [fst,lst) for a succession of count an elements, the search_n() function can be used in the C++ language. The following can be the general syntax of the search_n() function :

template <class FrwrdItrtr, class Sz, class S>
   FrwrdItrtr search_n ( FrwrdItrtr fst, FrwrdItrtr lst,
                              Sz cnt, const S& value );

[Modifier]

The following listed parameters of the search_n() function can help's you to use the search_n() function properly :
1. value : This parameter can be used to compare the Individual value or it can be used as an argument for predicate.
2. fst, lst : These parameters can be used for the forward iterators to the final and starting positions of the sequence that can be searched. The range used can be as [first,last).
3. cnt : This parameter can be used for the Minimum number of successive an elements that can be meeting the predicate that can be considered as match.

[Praetor]

Program :

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
bool mypredicate (int p, int q) 
{
  return (p==q);
}
int main ()
 {
  int mints[]={10,20,30,30,20,10,10,20};
  vector<int> mvctr (mints,mints+8);
  vector<int>::iterator i;
  i = search_n (mvctr.begin(), mvctr.end(), 2, 30);
  if (i!=mvctr.end())
    cout << "two 30s found at position " << int(i-mvctr.begin()) << endl;
  else
    cout << "match not found" << endl;
  i = search_n (mvctr.begin(), mvctr.end(), 2, 10, mprdct);
  if (i!=mvctr.end())
    cout << "two 10s found at position " << int(i-mvctr.begin()) << endl;
  else
    cout << "match not found" << endl;
    return 0;
}

Output :

Two 30s found at position 2
Two 10s found at position 5

[Katty]

The following code of lines can help you to learn the search_n() function more precisely :

      #include <algorithm>
      #include <list>
      #include <iostream>
      int main ()
      {
      #ifndef _RWSTD_NO_NAMESPACE
        using namespace std;
      #endif
        char sq[40]    = "Here's a string with a substring in it";
        char sbsq[10] = "substring";
        list<char,allocator<char> > sequence(sq, sq+38);
        list<char,allocator<char> > subseqnc(sbsq, sbsq+9);
        cout << endl << "The subsequence, " << sbsq 
             << ", was found at the ";
        cout << endl << "location identified by a '*'" 
             << endl << "     ";
        list<char,allocator<char> >::iterator plc;
        plc = search(squnc.begin(), squnc.end(),
                       sbsqnc.begin(), sbsqnc.end());
        *plc = '*';
        for (list<char,allocator<char> >::iterator j = 
             squnc.begin(); j != squnc.end(); j++)
          cout << *j;
        cout << endl;
       return 0;
      }

The Output of the above Program :

      The subsequence, substring, was found at the 
      location identified by a '*'
           Here's a string with a *ubstring in it

[kelfro]

Program :

#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
#include <functional>
#include <numeric>
template <class S>
inline void PRINTELEMENTS (const S& cl, const char* optstr="")
{
    typename S::constiterator ps;
    std::cout << optstr;
    for (ps=cl.begin(); ps!=cl.end(); ++ps) 
{
        std::cout << *ps << ' ';
    }
    std::cout << std::endl;
}
template <class S>
inline void INSERTELEMENTS (S& cl, int fst, int lst)
{
    for (int a=fst; a<=lst; ++a) 
{
        cl.insert(cl.end(),a);
    }
}
using namespace std;
int main()
{
   deque<int> cl;
   INSERTELEMENTS(cl,1,9);
   PRINTELEMENTS(cl);
   deque<int>::iterator ps;
   ps = search_n (cl.begin(), cl.end(), 4, 3);                    
   if (ps != cl.end()) 
{
       cout << "four consecutive elements with value 3 "
            << "start with " << distance(cl.begin(),ps) +1
            << ". element" << endl;
   }
   else 
{
       cout << "no four consecutive elements with value 3 found"
            << endl;
   }
}

Output :

1 2 3 4 5 6 7 8 9
no four consecutive elements with value 3 found