C++ STL algorithm, lexicographical_compare() code 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)
Other info: none
To do: Using the C++ lexicographical_compare() to compare element by element between two sequences to determine which is lesser of the two in C++ programming
To show: How to use the C++ algorithm, lexicographical_compare() to compare element by element between two sequences to determine which is lesser of the two in C++ programming
// C++ STL algorithm, lexicographical_compare()
#include <vector>
#include <list>
#include <algorithm>
#include <iostream>
using namespace std;
// return whether second element is twice the first
bool twice(int elem1, int elem2)
{return ((2*elem1) < elem2);}
int main(void)
{
// vector containers
vector <int> vec1, vec2;
// list container
list <int> lst;
// vector iterators
vector <int>::iterator Iter1, Iter2;
// list iterators
list <int>::iterator lst_Iter, lst_inIter;
int i, j, k;
bool result1, result2, result3;
// pushing/inserting data
for(i = 0; i <= 5; i++)
vec1.push_back(5*i);
for(j = 0; j <= 6; j++)
lst.push_back(5*j);
for(k = 0; k <= 5; k++)
vec2.push_back(10*k);
// printing data
cout<<"vec1 vector data: ";
for(Iter1 = vec1.begin(); Iter1 != vec1.end(); Iter1++)
cout<<*Iter1<<" ";
cout<<endl;
cout<<"lst list data: ";
for(lst_Iter = lst.begin(); lst_Iter != lst.end(); lst_Iter++)
cout<<*lst_Iter<<" ";
cout<<endl;
cout<<"vec2 vector data: ";
for(Iter2 = vec2.begin(); Iter2 != vec2.end(); Iter2++)
cout<<*Iter2<<" ";
cout<<endl;
// self lexicographical_comparison() of vec1 under identity
cout<<"\nOperation: lexicographical_compare(vec1.begin(), vec1.end(), vec2.begin(), vec2.end())"<<endl;
result1 = lexicographical_compare(vec1.begin(), vec1.end(), vec2.begin(), vec2.end());
if(result1)
cout<<"vec1 vector is lexicographically_less than vec2 vector"<<endl;
else
cout<<"vec1 vector is not lexicographically_less than vec2 vector"<<endl;
// lexicographical_comparison() of vec1 and lst under identity
cout<<"\nOperation: lexicographical_compare(vec1.begin(), vec1.end(), lst.begin(), lst.end())"<<endl;
result2 = lexicographical_compare(vec1.begin(), vec1.end(), lst.begin(), lst.end());
if(result2)
cout<<"vec1 vector is lexicographically_less than lst list"<<endl;
else
cout<<"vec1 vector is lexicographically_less than lst list"<<endl;
cout<<"\nOperation: lexicographical_compare(vec1.begin(), vec1.end(), vec2.begin(), vec2.end(), twice)"<<endl;
result3 = lexicographical_compare(vec1.begin(), vec1.end(), vec2.begin(), vec2.end(), twice);
if(result3)
cout<<"vec1 vector is lexicographically_less than vec2 vector based on twice()"<<endl;
else
cout<<"vec1 vector is not lexicographically_less than vec2 vector based on twice()"<<endl;
return 0;
}
Output examples:
vec1 vector data: 0 5 10 15 20 25
lst list data: 0 5 10 15 20 25 30
vec2 vector data: 0 10 20 30 40 50
Operation: lexicographical_compare(vec1.begin(), vec1.end(), vec2.begin(), vec2.end())
vec1 vector is lexicographically_less than vec2 vector
Operation: lexicographical_compare(vec1.begin(), vec1.end(), lst.begin(), lst.end())
vec1 vector is lexicographically_less than lst list
Operation: lexicographical_compare(vec1.begin(), vec1.end(), vec2.begin(), vec2.end(), twice)
vec1 vector is not lexicographically_less than vec2 vector based on twice()
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