Wall hack not working

I am using wallhack class and I don't get wallhack, what i get is see through players. When i try Memcpy wallhack that doesn't work either :'( I am running Windows 7 64 bit

Code i am using:

class cWallHack;
class cWallHack
{
public:
float WallHack;
char _0x0004[60];
};
cWallHack* pWallHack;



pWallHack = (cWallHack*)0x175A554;
pWallHack->WallHack = 15;