Illustrates how to use the predicate version of the next_permutation Standard Template Library (STL) function in Visual C++.
template<class BidirectionalIterator, class Compare> inline
bool next_permutation(
BidirectionalIterator First,
BidirectionalIterator Last,
Compare Compare
)
Remarks
备注
The class/parameter names in the prototype do not match the version in the header file. Some have been modified to improve readability.
The next_permutation algorithm changes the order of the elements in the range [First, Last) to the next lexicographic permutation and returns true. If there is no next_permutation, it arranges the sequence to be the first permutation and returns false.
备注
The next_permutation algorithm assumes that the sequence is sorted in ascending order using the compare function. The nonpredicate version uses the compare function to order the permutations.
Example
// next_permutationPV.cpp
// compile with: /EHsc
// Illustrates how to use the predicate version
// of the next_permutation function.
//
// Functions:
// next_permutation : Change the order of the sequence to the
// next lexicograhic permutation.
// disable warning C4786: symbol greater than 255 character,
// okay to ignore
#pragma warning(disable: 4786)
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <functional>
using namespace std ;
int main()
{
const int VECTOR_SIZE = 3 ;
// Define a template class vector of strings
typedef vector<string> StrVector ;
//Define an iterator for template class vector of strings
typedef StrVector::iterator StrVectorIt ;
//Define an ostream iterator for strings
typedef ostream_iterator<string> StrOstreamIt;
StrVector Pattern(VECTOR_SIZE);
StrVectorIt start, end, it;
StrOstreamIt outIt(cout, " ");
// location of first element of Pattern
start = Pattern.begin();
// one past the location last element of Pattern
end = Pattern.end();
// Initialize vector Pattern
Pattern[0] = "K" ;
Pattern[1] = "A" ;
Pattern[2] = "L" ;
// sort the contents of Pattern, required by next_permutation
sort(start, end, less<string>()) ;
// print content of Pattern
cout << "Before calling next_permutation..." << endl << "Pattern:" ;
for (it = start; it != end; it++)
cout << " " << *it;
cout << endl;
// Generate all possible permutations
cout << "After calling next_permutation...." << endl;
while ( next_permutation(start, end, less<string>()) )
{
copy(start, end, outIt) ;
cout << endl ;
}
}
Sample Output
Before calling next_permutation:
Pattern: A K L
After calling next_permutation:.
A L K
K A L
K L A
L A K
L K A
Requirements
Header: <algorithm>