Loop through entities in source engine.

entityLoop.cpp

/*
By Nomster
http://www.unknowncheats.me/forum/781373-post1.html
*/
CEntityList* gpMainEntityList = ( CEntityList* )( dwGameClient + 0x22321C0 );

for( int i = 0; i < MAX_ENTITY_NUM; i++ )
{
	if( gpEntityList[ i ] )
	{
		//...
	}
}

#define MAX_ENTITY_NUM 	0x2800

DWORD gHighestActiveEntityIndex = *( DWORD *)( dwGameClient + 0x24F845C ); //U can also use this instead of max_entity_num

entityLoop.h

/*
By Nomster
http://www.unknowncheats.me/forum/781373-post1.html
*/
class CEntityList;
class CEntity;
class CEntityInfo;
class CEntityHealth;

class CEntityList
{
public:
	CEntity** pEntity; //0x02F0 
};

class CEntity
{
public:
char _0x0000[52];
	D3DXVECTOR3 vPos0; //0x0034 
char _0x0040[8];
	D3DXVECTOR3 vPos1; //0x0048 
char _0x0054[40];
	char cIdentity[64]; //0x007C 
char _0x00BC[148];
	CEntityInfo* pEntInfo; //0x0150 
	CEntityInfo* pSecondaryInfo; //0x0154 
char _0x0158[72];
	CEntityHealth* pEntityHealth; //0x01A0 
char _0x01A4[668];

};//Size=0x0440

class CEntityInfo
{
public:
	CHAR* pName; //0x0000 
char _0x0004[60];

};//Size=0x0040

class CEntityHealth
{
public:
	float fCurrentHP; //0x0000 
	float fMaximumHP; //0x0004 
char _0x0008[56];

};//Size=0x0040