stable_sort(3C++) - stable_sort(3C++)
Standard C++ Library Copyright 1998, Rogue Wave Software, Inc.
NAMEstable_sort
- A templatized 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 compari‐
son function comp.
The stable_sort algorithm is considered stable because the relative
order of the equal elements is preserved.
COMPLEXITYstable_sort does at most N(logN)2 comparisons, where N equals
last - first. If enough extra memory is available, it does at most
NlogN.
EXAMPLE
//
// sort.cpp
//
#include <vector>
#include <algorithm>
#include <functional>
#include <iostream>
using namespace std;
struct associate
{
int num;
char chr;
associate(int n, char c) : num(n), chr(c) {};
associate() : num(0), chr(`\0'){};
};
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;
}
Program OutputOriginal 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; >
WARNINGS
If your compiler does not support default template parameters, then you
always need to supply the Allocator template argument. For instance,
you need to write:
vector<int, allocator>
instead of:
vector<int>
If your compiler does not support namespaces, then you do not need the
using declaration for std.
SEE ALSO
sort, partial_sort, partial_sort_copy
Rogue Wave Software 02 Apr 1998 stable_sort(3C++)
