Cpp > Programs

ReverseCompare cpp example

#include <iostream>
#include <vector>
#include <functional>
#include <algorithm>
using namespace std;

//
// Unary function to output its argument to cout
//
template<class T>
class Print: public unary_function<T, void>
{
public:
void operator()(T& arg1)
{
cout << arg1 << " ";
}
};

//
// Compare function
//
bool ReverseCompare(int arg1, int arg2);

//
// Display all elements in a container
//
template<class Container>
void ShowElements(Container& c, char* text);

int main()
{
typedef vector<int> VectorInt;
typedef VectorInt::iterator Itor;

// create an integer vector
VectorInt vInt1(7);
Itor first1 = vInt1.begin();
Itor last1 = vInt1.end();
generate(first1, last1, rand);
ShowElements(vInt1, "Random number sequence");

// sort the sequence in descending order
nth_element(first1, first1 + 1, last1, ReverseCompare);
ShowElements(vInt1, "After nth_element()");

return 0;
}

//
// Compare function
//
bool ReverseCompare(int arg1, int arg2)
{
return (arg1 > arg2);
}

//
// Display all elements in a container
//
template<class Container>
void ShowElements(Container& c, char* text)
{
Print<Container::value_type> DoPrint;

cout << text << ":\n";
for_each(c.begin(), c.end(), DoPrint);
cout << "\n\n";
}