C++ STL algorithm, inplace_merge() program example
Compiler: Visual C++ Express Edition 2005
Compiled on Platform: Windows XP Pro SP2
Header file: Standard
Additional project setting: Set project to be compiled as C++
Project -> your_project_name Properties -> Configuration Properties -> C/C++ -> Advanced -> Compiled As: Compiled as C++ Code (/TP)
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To do: Using the C++ inplace_merge() to combine the elements from two consecutive sorted ranges into a single sorted range, where the ordering criterion may be specified by a binary predicate in C++ programming
To show: How to use the C++ algorithm, inplace_merge() to combine the elements from two consecutive sorted ranges into a single sorted range, where the ordering criterion may be specified by a binary predicate in C++ programming
// C++ STL algorithm, inplace_merge()
#include <vector>
#include <algorithm>
// for greater<int>()
#include <functional>
#include <iostream>
using namespace std;
// return whether modulus of elem1 is less than modulus of elem2
bool mod_lesser(int elem1, int elem2)
{
if(elem1 < 0)
elem1 = - elem1;
if(elem2 < 0)
elem2 = - elem2;
return (elem1 < elem2);
}
int main(void)
{
// vector container
vector <int> vec1;
// vector iterators
vector <int>::iterator Iter1, Iter2, Iter3;
int i, j;
// constructing vector vec1 with default less-than ordering
//
// pushing data
for(i = 0; i <= 5; i++)
vec1.push_back(i);
for(j =-5; j <= 0; j++)
vec1.push_back(j);
// printing data
cout<<"vec1 vector data with subranges sorted by the binary predicate less than is: ";
for(Iter1 = vec1.begin(); Iter1 != vec1.end(); Iter1++)
cout<<*Iter1<<" ";
cout<<endl;
// constructing vector vec2 with ranges sorted by greater
//
// vector container
vector <int> vec2(vec1);
// vector iterator
vector <int>::iterator break2;
break2 = find(vec2.begin(), vec2.end(), -5);
// do some sorting
sort(vec2.begin(), break2, greater<int>());
sort(break2, vec2.end(), greater<int>());
// printing data
cout<<"\nvec2 vector data with subranges sorted by the binary predicate greater is: ";
for(Iter2 = vec2.begin(); Iter2 != vec2.end(); Iter2++)
cout<<*Iter2<<" ";
cout<<endl;
// constructing vector vec3 with ranges sorted by mod_lesser()
//
// vector container
vector <int> vec3(vec1);
// vector iterator
vector <int>::iterator break3;
break3 = find(vec3.begin(), vec3.end(), -5);
// do some sorting
sort(vec3.begin(), break3, mod_lesser);
sort(break3, vec3.end(), mod_lesser);
// printing data
cout<<"\nvec3 vector data with subranges sorted by the binary predicate mod_lesser is: ";
for(Iter3 = vec3.begin(); Iter3 != vec3.end(); Iter3++)
cout<<*Iter3<<" ";
cout<<endl;
// another vector iterator
vector <int>::iterator break1;
break1 = find(vec1.begin(), vec1.end(), -5);
// inplace_merge() operation
inplace_merge(vec1.begin(), break1, vec1.end());
// printing
cout<<"\nvec1merg vector data, inplace_merge() with default order: ";
for(Iter1 = vec1.begin(); Iter1 != vec1.end(); Iter1++)
cout<<*Iter1<<" ";
cout<<endl;
// to merge inplace in descending order, specify binary predicate greater<int>()
inplace_merge(vec2.begin(), break2, vec2.end(), greater<int>());
cout<<"\nvec2merg vector data, inplace_merge() with binary predicate greater specified: ";
for(Iter2 = vec2.begin(); Iter2 != vec2.end(); Iter2++)
cout<<*Iter2<<" ";
cout<<endl;
// applying a user defined binary predicate mod_lesser()
inplace_merge(vec3.begin(), break3, vec3.end(), mod_lesser);
cout<<"\nvec3merg vector data, merged inplace with binary predicate mod_lesser specified: ";
for(Iter3 = vec3.begin(); Iter3 != vec3.end(); Iter3++)
cout<<*Iter3<<" ";
cout<<endl;
return 0;
}
Output examples:
vec1 vector data with subranges sorted by the binary predicate less than is: 0 1 2 3 4 5 -5 -4 -3 -2 -1 0
vec2 vector data with subranges sorted by the binary predicate greater is: 5 4 3 2 1 0 0 -1 -2 -3 -4 -5
vec3 vector data with subranges sorted by the binary predicate mod_lesser is: 0 1 2 3 4 5 0 -1 -2 -3 -4 -5
vec1merg vector data, inplace_merge() with default order: -5 -4 -3 -2 -1 0 0 1 2 3 4 5
vec2merg vector data, inplace_merge() with binary predicate greater specified: 5 4 3 2 1 0 0 -1 -2 -3 -4 -5
vec3merg vector data, merged inplace with binary predicate mod_lesser specified: 0 0 1 -1 2 -2 3 -3 4 -4 5 -5
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