set_difference

Header

template<class InputIterator1, class InputIterator2, class OutputIterator>
OutputIterator set_difference(InputIterator1 first1, InputIterator1 last1, InputIterator first2, InputIterator2 last2, OutputIterator result)

Creates a sorted set of elements in the first set that are not in the set sequence. The first set is represented by the range [first1, last1). The second set is represented by the range [first2, last2). The resulting set is placed in the range starting at result.

The non-predicate version uses operator< for comparison.

template<class InputIterator1, class InputIterator2, class OutputIterator, class BinaryPredicate>
OutputIterator set_difference(InputIterator1 first1, InputIterator1 last1, InputIterator first2, InputIterator2 last2, OutputIterator result, BinaryPredicate pr)

Creates a sorted set of elements in the first set that are not in the second set. The first set is represented by the range [first1, last1). The second set is represented by the range [first2, last2). The resulting set is placed in the range starting at result.

The predicate version uses the predicate function pr for comparison.

Sample

#pragma warning(disable : 4786)

#include <algorithm>
#include <iostream>
#include <functional>
#include <cstring>

int main()
{
	char *Alphabet = "abcdefghijklmnopqrstuvwxyz" ;
	char *Vowels = "aeiou" ;
	char *AlphaNum = "1234567890abcdef" ;
	char result[45] ;
	char *last ;

	int lenA = strlen(Alphabet) ;
	int lenV = strlen(Vowels) ;
	int lenAN = strlen(AlphaNum) ;

	std::cout << "Alphabet = " << Alphabet << std::endl ;
	std::cout << "\nVowels = " << Vowels << std::endl ;
	std::cout << "\nAlphaNum = " << AlphaNum << std::endl ;
	
	std::cout << "\n\nusing non-predicate versions" << std::endl ;
	
	//non-predicate set_difference
	last = std::set_difference(Alphabet, Alphabet+lenA,
							AlphaNum, AlphaNum+lenAN,
							result) ;
	*last = 0 ;
	std::cout << "\nset_difference(Alphabet, AlphaNum) =  " << result << std::endl ;
	
	//non-predicate set_intersection
	last = std::set_intersection(Alphabet, Alphabet+lenA,
							AlphaNum, AlphaNum+lenAN,
							result) ;
	*last = 0 ;
	std::cout << "\nset_intersection(Alphabet, AlphaNum) =  " << result << std::endl ;

	//non-predicate set_symmetric_difference
	last = std::set_symmetric_difference(Alphabet, Alphabet+lenA,
							Vowels, Vowels+lenAN,
							result) ;
	*last = 0 ;
	std::cout << "\nset_symmetric_difference(Alphabet, Vowels) =  " << 
		result << std::endl ;

	//non-predicate set_union
	last = std::set_union(Alphabet, Alphabet+lenA,
							AlphaNum, AlphaNum+lenAN,
							result) ;
	*last = 0 ;
	std::cout << "\nset_union(Alphabet, AlphaNum) =  " << result << std::endl ;

	std::cout << "\n\nusing predicate versions" << std::endl ;

	//predicate set_difference
	last = std::set_difference(Alphabet, Alphabet+lenA,
							AlphaNum, AlphaNum+lenAN,
							result, std::less<char>()) ;
	*last = 0 ;
	std::cout << "\nset_difference(Alphabet, AlphaNum) =  " << result << std::endl ;
	
	//predicate set_intersection
	last = std::set_intersection(Alphabet, Alphabet+lenA,
							AlphaNum, AlphaNum+lenAN,
							result, std::less<char>()) ;
	*last = 0 ;
	std::cout << "\nset_intersection(Alphabet, AlphaNum) =  " << result << std::endl ;

	//predicate set_symmetric_difference
	last = std::set_symmetric_difference(Alphabet, Alphabet+lenA,
							Vowels, Vowels+lenAN,
							result, std::less<char>()) ;
	*last = 0 ;
	std::cout << "\nset_symmetric_difference(Alphabet, Vowels) =  " << 
		result << std::endl ;

	//predicate set_union
	last = std::set_union(Alphabet, Alphabet+lenA,
							AlphaNum, AlphaNum+lenAN,
							result, std::less<char>()) ;
	*last = 0 ;
	std::cout << "\nset_union(Alphabet, AlphaNum) =  " << result << std::endl ;


	return 0 ;
}

Program Output

Alphabet = abcdefghijklmnopqrstuvwxyz

Vowels = aeiou

AlphaNum = 1234567890abcdef


using non-predicate versions

set_difference(Alphabet, AlphaNum) =  ghijklmnopqrstuvwxyz

set_intersection(Alphabet, AlphaNum) =  abcdef

set_symmetric_difference(Alphabet, Vowels) =  bcdfghjklmnpqrst

set_union(Alphabet, AlphaNum) =  1234567890abcdefghijklmnopqrstuvwxyz


using predicate versions

set_difference(Alphabet, AlphaNum) =  ghijklmnopqrstuvwxyz

set_intersection(Alphabet, AlphaNum) =  abcdef

set_symmetric_difference(Alphabet, Vowels) =  bcdfghjklmnpqrst

set_union(Alphabet, AlphaNum) =  1234567890abcdefghijklmnopqrstuvwxyz