stable_sort (3C++std) - Tru64 UNIX
Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc. NAME
stable_sort - Templated algorithm for sorting collections of entities.
SYNOPSIS
#include <algorithm>
template <class RandomAccessIterator>
void stable_sort (RandomAccessIterator first,
RandomAccessIterator last);
template <class RandomAccessIterator, class Compare>
void stable_sort (RandomAccessIterator first,
RandomAccessIterator last,
Compare comp);
DESCRIPTION
The stable_sort algorithm sorts the elements in the range [first, last).
The first version of the algorithm uses less than (<) as the comparison
operator for the sort. The second version uses the comparison function
comp.
The stable_sort algorithm is considered stable because the relative order
of the equal elements is preserved.
COMPLEXITY
stable_sort does at most N(logN) **2, where N equals last -first,
comparisons; if enough extra memory is available, it is NlogN.
EXAMPLE
//
// sort.cpp
//
#include <vector>
#include <algorithm>
#include <functional>
#include <iostream.h>
struct associate
{
int num;
char chr;
associate(int n, char c) : num(n), chr(c){};
associate() : num(0), chr(' '){};
};
bool operator<(const associate &x, const associate &y)
{
return x.num < y.num;
}
ostream& operator<<(ostream &s, const associate &x)
{
return s << "<" << x.num << ";" << x.chr << ">";
}
int main ()
{
vector<associate>::iterator i, j, k;
associate arr[20] =
{associate(-4, ' '), associate(16, ' '),
associate(17, ' '), associate(-3, 's'),
associate(14, ' '), associate(-6, ' '),
associate(-1, ' '), associate(-3, 't'),
associate(23, ' '), associate(-3, 'a'),
associate(-2, ' '), associate(-7, ' '),
associate(-3, 'b'), associate(-8, ' '),
associate(11, ' '), associate(-3, 'l'),
associate(15, ' '), associate(-5, ' '),
associate(-3, 'e'), associate(15, ' ')};
// Set up vectors
vector<associate> v(arr, arr+20), v1((size_t)20),
v2((size_t)20);
// Copy original vector to vectors #1 and #2
copy(v.begin(), v.end(), v1.begin());
copy(v.begin(), v.end(), v2.begin());
// Sort vector #1
sort(v1.begin(), v1.end());
// Stable sort vector #2
stable_sort(v2.begin(), v2.end());
// Display the results
cout << "Original sort stable_sort" << endl;
for(i = v.begin(), j = v1.begin(), k = v2.begin();
i != v.end(); i++, j++, k++)
cout << *i << " " << *j << " " << *k << endl;
return 0;
}
Output :
Original sort stable_sort
<-4; > <-8; > <-8; >
<16; > <-7; > <-7; >
<17; > <-6; > <-6; >
<-3;s> <-5; > <-5; >
<14; > <-4; > <-4; >
<-6; > <-3;e> <-3;s>
<-1; > <-3;s> <-3;t>
<-3;t> <-3;l> <-3;a>
<23; > <-3;t> <-3;b>
<-3;a> <-3;b> <-3;l>
<-2; > <-3;a> <-3;e>
<-7; > <-2; > <-2; >
<-3;b> <-1; > <-1; >
<-8; > <11; > <11; >
<11; > <14; > <14; >
<-3;l> <15; > <15; >
<15; > <15; > <15; >
<-5; > <16; > <16; >
<-3;e> <17; > <17; >
<15; > <23; > <23; >
WARNING
If your compiler does not support default template parameters, then you
need to always supply the Allocator template argument. For instance, you
will need to write :
vector<int, allocator>
instead of :
vector<int>
SEE ALSO
sort, partial_sort, partial_sort_copy
STANDARDS CONFORMANCE
ANSI X3J16/ISO WG21 Joint C++ Committee
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