Print gravity with Box2D 2.4.2

hello-box2d-v2-cpp.cpp

#include <box2d/box2d.h>
#include <iostream>

int main()
{
    b2Vec2 gravity(0.f, -9.8f);
    b2World* world = new b2World(gravity);
    float gx = world->GetGravity().x;
    float gy = world->GetGravity().y;
    std::cout << "gravity = (" << gx << ", " << gy << ")" << std::endl;
	return 0;
}