How to cycle through entities without C_scan or c_trace

you = ent_next(NULL);
while(you)
{
	ENTITY* you2 = you;
	you = ent_next(you);
	if(you2._type == type_ball) ptr_remove(you2);
}

function RemoveMolecules()
{
	while(NoOfMolecules != (n + 1))
	{
		you = ent_next(NULL);
		while(you)
		{
			ENTITY* PointAndKill = you;
			you = ent_next(you);
			
			if(PointAndKill.skill51 == 3619)
			{								
				NoOfMolecules = NoOfMolecules - 1;
				ptr_remove(PointAndKill);
			}
			wait(1);
		}
	}
}

void main()
{
	fps_max = 60;
	level_load(NULL);
	var i;
	for(i = 0; i < 100; i++)
	{
		you = ent_create(CUBE_MDL,vector(50+random(200),random(100)-50,random(100)-50),NULL);
		your.skill1 = i%2;
	}
	wait(-2);
	you = ent_next(NULL);
	while(you)
	{
		ENTITY* you2 = you;
		you = ent_next(you);
		if(!you2.skill1) ptr_remove(you2);
	}
	wait(-1);
	you = ent_next(NULL);
	while(you)
	{
		ENTITY* you2 = you;
		you = ent_next(you);
		ptr_remove(you2);
	}
	wait(-1);
	for(i = 0; i < 100; i++)
	{
		you = ent_create(SPHERE_MDL,vector(50+random(200),random(100)-50,random(100)-50),NULL);
		you = ent_create(CUBE_MDL,vector(50+random(200),random(100)-50,random(100)-50),NULL);
		your.skill1 = 123; // only remove cubes
	}
	wait(-2);
	you = ent_next(NULL);
	while(you && i > 50) // i == 100 at start
	{
		ENTITY* you2 = you;
		you = ent_next(you);
		if(you2.skill1 == 123) // remove half of the cubes
		{
			ptr_remove(you2);
			i--;
		}
	}
}

function RemoveMolecules()
{
	NoOfMolecules = NoOfMolecules - 1;
	NoOfMolecules = clamp(NoOfMolecules, 2, 31);
	you = ent_next(NULL);
	while(you)
	{
		ENTITY* PointAndKill = you;
		you = ent_next(you);
		if(PointAndKill.skill51 > NoOfMolecules || PointAndKill.skill51 == NoOfMolecules)
		{								
			ptr_remove(PointAndKill);
		}
		wait(1);		
	}
}

function DecreaseVolumeInEngine()
{
	VolumeChanging = 1;
	
	/*Cycle through molecules and move them all to spawn point before deleting the container.
	Otherwise, the container will shrink past the location of some molecules, leaving them
	outside*/
	var teleported = 0;
	you = ent_next(NULL);
	while(NoOfMolecules > teleported)
	{
		ENTITY* NextMolecule = you;
		you = ent_next(you);
		if(NextMolecule.skill51) //if it has a skill51, meaning its a molecule
		{
			NextMolecule.x = (SpawnPoint.x + (2000*V)) + random(100);
			NextMolecule.y = (SpawnPoint.y + (2000*V)) + random(100);
			NextMolecule.z = (SpawnPoint.z + (2000*V)) + random(100);
		}
		teleported+=1;
		wait(1);
	}
	
	ent_remove(Container);
	Container = ent_create("HollowCube.WMB", vector(0, 0, 0), ResizeTheCube);
	wait(-1);
	VolumeChanging = 0;
	wait(1);	
	
	//Center the camera behind the cube. New camera location is dependent on V (Volume of Cube)
//	camera.x -= V * 13000;
//	camera.y += V * 5000;
//	camera.z += V * 5000;
//	wait(1);
}