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#include <algorithm>
#include <iostream>
#include <string>
#include <cstring>
#include <iterator>
using namespace std;
class CaseString
{
public:
bool operator()(string const &first, string const &second) const
{
return strcasecmp(first.c_str(), second.c_str()) < 0;
}
};
int main()
{
string saints[] = {"Oh", "when", "the", "saints"};
cout << "All previous permutations of 'Oh when the saints':\n";
cout << "Sequences:\n";
do
{
copy(saints, saints + 4, ostream_iterator<string>{ cout, " " });
cout << '\n';
}
while (prev_permutation(saints, saints + 4, CaseString{}));
cout << "After first sorting the sequence:\n";
sort(saints, saints + 4, CaseString{});
cout << "Sequences:\n";
while (prev_permutation(saints, saints + 4, CaseString{}))
{
copy(saints, saints + 4, ostream_iterator<string>{ cout, " " });
cout << '\n';
}
cout << "No (more) previous permutations\n";
}
/*
Displays:
All previous permutations of 'Oh when the saints':
Sequences:
Oh when the saints
Oh when saints the
Oh the when saints
Oh the saints when
Oh saints when the
Oh saints the when
After first sorting the sequence:
Sequences:
No (more) previous permutations
*/
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