next_permutation (STL Samples)
Illustrates how to use the next_permutation Standard Template Library (STL) function in Visual C++.
template<class BidirectionalIterator> inline
bool next_permutation(
BidirectionalIterator First,
BidirectionalIterator Last
)
Remarks
注意
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.
注意
The next_permutation algorithm assumes that the sequence is sorted in ascending order using operator<. The nonpredicate version uses the operator< to order the permutations.
Example
// next_permutation.cpp
// compile with: /EHsc
// Illustrates how to use 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, " ") ;
start = Pattern.begin() ; // location of first
// element of Pattern
end = Pattern.end() ; // one past the location last
// element of Pattern
//Initialize vector Pattern
Pattern[0] = "A" ;
Pattern[1] = "B" ;
Pattern[2] = "C" ;
// print content of Pattern
cout << "Before calling next_permutation:\n" << "Pattern: " ;
for(it = start; it != end; it++)
cout << *it << " " ;
cout << "\n\n" ;
// Generate all possible permutations
cout << "After calling next_permutation:" << endl ;
while ( next_permutation(start, end) )
{
copy(start, end, outIt) ;
cout << endl ;
}
}
Output
Before calling next_permutation:
Pattern: A B C
After calling next_permutation:
A C B
B A C
B C A
C A B
C B A
Requirements
Header: <algorithm>