Sort STL Vector which contain struct

  
// Function object to sort by ascending Z order

struct SortByZValAsc
{
	bool operator()(const point3D& p1, const point3D& p2)
	{ return p1.z < p2.z;}
};

// Function object to sort by descending Z order

struct SortByZValDesc
{
	bool operator()(const point3D& p1, const point3D& p2)
	{ return p2.z < p1.z; }
};
  

  
sort(v.begin(), v.end(), SortByZValAsc());
// or

sort(v.begin(), v.end(), SortByZValDesc());
  

  
#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

// Your point structure

struct point3D
{
	float x,y,z;
	point3D(float ix, float iy, float iz) : x(ix), y(iy), z(iz) {}
};

// Function object to sort by ascending Z order

struct SortByZValAsc
{
	bool operator()(const point3D& p1, const point3D& p2)
	{ return p1.z < p2.z;}
};

// Function object to sort by descending Z order

struct SortByZValDesc
{
	bool operator()(const point3D& p1, const point3D& p2)
	{ return p2.z < p1.z; }
};

int main()
{
	// Fill in a vector with points (in random Z order)

	vector<point3D> v;
	v.push_back(point3D(3.0f,0.0f,1.3f));
	v.push_back(point3D(-5.0f,0.0f,0.3f));
	v.push_back(point3D(3.0f,2.0f,6.3f));
	v.push_back(point3D(1.0f,0.0f,7.3f));

	// Sort list by ascending

	sort(v.begin(), v.end(), less<point3D> ());

	// Print the list in its new order

	cout << "List in ascending Z order" << endl;
	vector<point3D>::iterator it = v.begin();
	for(;it!=v.end(); it++)
		cout << it->x << ", " << it->y << ", " << it->z << endl;

	// Sort list by descending

	sort(v.begin(), v.end(), SortByZValDesc());

	// Print the list in its new order

	cout << "\nList in ascending Z order" << endl;
	it = v.begin();
	for(;it!=v.end(); it++)
		cout << it->x << ", " << it->y << ", " << it->z << endl;

	return 0;
}