How can I use the find_first_of() in C++

[Gavyn]

Hello, Everybody. I am the student of the MSC-IT second year. I have to create the on the find_first_of() function of the C++ language. I can have the knowledge of the functions that can be in-built in the the C++ language. So, I want to know about the find_first_of() function of the C++ function. I also want to know how the find_first_of() function can be used in the C++ language. Can anyone has the solution on find_first_of() function then reply me!!

[opaper]

The find_first_of() function that can be used to find an element from the given set in specified range. The following can be the general syntax of the find_first_of() function as follows :
template <class FrwrdItrtr1, class FrwrdItrtr2>
FrwrdItrtr1 find_first_of ( FrwrdItrtr1 fst1, FrwrdItrtr1 lst1, FrwrdItrtr2 fst2, FrwrdItrtr2 lst2 );

[MindSpace]

The following code of lines demonstrates you about find_first_of() function in the C++ language As :

#include <iostream>
#include <algorithm>
#include <cctype>
#include <vector>
using namespace std;
bool compcaseinsensitive (char D1, char D2) 
{
  return (tolower(D1)==tolower(D2));
}
int main () 
{
  int mchrs[] = {'a','b','c','A','B','C'};
  vector<char> mvctr (mchrs,mchrs+6);
  vector<char>::iterator t;
  int match[] = {'A','B','C'};
  t = find_first_of (mvctr.begin(), mvctr.end(), match, match+3);
  if (t!=mvctr.end())
    cout << "first match is: " << *t << endl;
  t = find_first_of (mvctr.begin(), mvctr.end(),
                      match, match+3, compcaseinsensitive);
  if (t!=mvctr.end())
    cout << "first match is: " << *t << endl;
 return 0;
}

The above code of lines can generate the following Output :

First match is: A
First match is: a

[Modifier]

There can be one more example on the find_first_of() function of C++ language for you :

#include <iostream>
using std::cout;
using std::endl;
#include <string>
using std::string;
int main()
{
   string strng1( "This is a test string!");
   int lct;
   lct = strng1.find_first_of( "is" );
   cout << "\n\n(find_first_of) found '" << strng1[ lct ]
      << "at: " << lct;
  return 0;
}

The following can be the out put of the above code :

(find_first_of) found 'iat: 2"

[Praetor]

The following can be the parameters of the function find_first_of() as listed below :
1. fst2, lst2 : These variables can be used for the forward iterators to the final and starting positions of an element values that can be searched for. The range used can be as [fst2,lst2).
2. fst1, lst1 : These variables can be used for forward iterators to the final and starting positions of the sequence that can be searched. The range used can be as [fst1,lst1).

[Katty]

Program :

      #include <algorithm>   
      #include <functional>   
      #include <iostream>     
      #include <vector>       
      int main ()
      {
           typedef std::vector<int, std::allocator<int> > vector;
          const vector::value_type a1[] = 
{ 
              0, 1, 2, 2, 3, 4, 2, 2, 6, 7 
          };
          const vector::value_type a2[] = { 6, 4 };
          const vector v1(a1, a1 + sizeof a1 / sizeof *a1);
          const vector v2(a2, a2 + sizeof a2 / sizeof *a2);
          vector::const_iterator it1 =
              std::find_first_of(v1.begin(), v1.end(), 
                                 v2.begin(), v2.end()); 
          vector::const_iterator it2 =
              std::find_first_of(v1.begin(), v1.end(), 
                                 v2.begin(), v2.end(),
                              std::equal_to<vector::value_type>());
          std::ostream_iterator<vector::value_type, char,
              std::char_traits<char> > out(std::cout, " " );
          std::cout << "For the vectors { ";
          std::copy(v1.begin(), v1.end(), out);
          std:: cout << "} and { ";
          std::copy(v2.begin(), v2.end(), out);
          std::cout << "}\nboth versions of find_first_of "
                    << "point to: " << *it1 << std::endl; 
          return !(*it1 == *it2);
      }

Output :

      For the vectors { 0 1 2 2 3 4 2 2 6 7 } and { 6 4 }
      both versions of find_first_of point to: 4