Using disjoint() with a comparison function. - C++ STL Algorithm

C++ examples for STL Algorithm:disjoint

  1. HOME
  2. C++
  3. STL Algorithm
  4. disjoint

Description

Using disjoint() with a comparison function.

Demo Code

#include <iostream>
#include <list>
#include <algorithm>
#include <cctype>
using namespace std;

template<class InIter>
void show_range(const char *msg, InIter start, InIter end);

template<class InIter>
bool disjoint(InIter start, InIter end,InIter start2, InIter end2);

// Overload disjoint() to take a comparison function.
template<class InIter, class Comp>
bool disjoint(InIter start, InIter end,InIter start2, InIter end2, Comp cmpfn);

bool equals_ignorecase(char ch1, char ch2);

int main()/*from   w  w  w  .j  a v a2s.  c om*/
{
   list<char> lst1, lst2;

   for(int i=0; i < 5; i++) lst1.push_back('A'+i);

   for(int i=2; i < 7; i++) lst2.push_back('a'+i);

   show_range("Contents of lst1: ", lst1.begin(), lst1.end());

   show_range("Contents of lst2: ", lst2.begin(), lst2.end());

   cout << endl;

   // Test lst1 and lst2.
   cout << "Testing lst1 and lst2 in a case-sensitive manner.\n";

   if(disjoint(lst1.begin(), lst1.end(), lst2.begin(), lst2.end()))
      cout << "lst1 and lst2 are disjoint\n";
   else 
      cout << "lst1 and lst2 are not disjoint.\n";
   cout << endl;

   // Test lst1 and lst2, but ignore case differences.

   cout << "Testing lst1 and lst2 while ignoring case differences.\n";

   if(disjoint(lst1.begin(), lst1.end(), lst2.begin(), lst2.end(), equals_ignorecase))
      cout << "lst1 and lst2 are disjoint\n";
   else 
      cout << "lst1 and lst2 are not disjoint.\n";
   return 0;
}
// Show a range of elements.
template<class InIter>
void show_range(const char *msg, InIter start, InIter end) {
   InIter itr;
   cout << msg;
   for(itr = start; itr != end; ++itr)
      cout << *itr << " ";
   cout << endl;
}
// determines if the contents of two ranges are disjoint. That is, if they contain no elements in common.
template<class InIter>
bool disjoint(InIter start, InIter end,InIter start2, InIter end2) {
   InIter itr;
   for( ; start != end; ++start)   {
      for(itr = start2; itr != end2; ++itr)
         if(*start == *itr) return false;
   }
   return true;
}
// This overload of disjoint() lets you specify a comparison function
// that determines when two elements are equal.
template<class InIter, class Comp>
bool disjoint(InIter start, InIter end, InIter start2, InIter end2, Comp cmpfn) {
      InIter itr;
      for( ; start != end; ++start)   {
         for(itr = start2; itr != end2; ++itr)
            if(cmpfn(*start, *itr)) return false;
      }
      return true;
}
// This function returns true if ch1 and ch2 represent the
// same letter despite case differences.
bool equals_ignorecase(char ch1, char ch2) {
     if(tolower(ch1) == tolower(ch2)) 
         return true;
     return false;
}

Result


Related Tutorials