   2 Unresolved externals - please help.
  Error11error LNK2019: unresolved external symbol "public: __thiscall GameMaterial::GameMaterial(void)" (??0GameMaterial@@QAE@XZ) referenced in function "void __cdecl CreateMaterialResource(class Material * *,char *,char *)" (?CreateMaterialResource@@YAXPAPAVMaterial@@PAD1@Z)Main.objError12fatal error LNK1120: 1 unresolved externalsC:\Users\Andrew Chinnadorai\Desktop\Solein\game1\Game.exeCan't find what's wrong:Where the error's coming from?This is GameMaterial.cpp:#include "Main.h"//-----------------------------------------------------------------------------// The game material class constructor.//-----------------------------------------------------------------------------GameMaterial::GameMaterial( char *name, char *path ) : Material( name, path ){// Load the script for this material.Script *script = new Script( name, path );// Store the step sounds.m_stepSounds = new LinkedList< Sound >;char stepSound[16] = { "step_sound0" };while( script->GetStringData( stepSound ) != NULL ){m_stepSounds->Add( new Sound( script->GetStringData( stepSound ) ) );sprintf( stepSound, "step_sound%d", m_stepSounds->GetTotalElements() );}// Destory the material's script.SAFE_DELETE( script );}//-----------------------------------------------------------------------------// The game material class destructor.//-----------------------------------------------------------------------------GameMaterial::~GameMaterial(){// Destroy the step sounds list.SAFE_DELETE( m_stepSounds );}//-----------------------------------------------------------------------------// Returns a random step sound from the list of step sounds.//-----------------------------------------------------------------------------Sound *GameMaterial::GetStepSound(){return m_stepSounds->GetRandom();}Where's the problem coming from(I've used /verbose before)Any help appreciate?Regards,   
  The linker is looking for the default constructor (the one that takes no arguments). Since you have defined a constructor that takes arguments, this supresses the automatically generated default constructor.Somewhere else you must be trying to instantiate on object of the type GameMaterial without providing arguments to the constructor.   ;  Your GameMaterial class declares a constructor, "GameMaterial();" in GameMaterial.hpp (I can deduce this with my psychic powers, since you've not shown us this file).  You have no corresponding definition of that constructor ala GameMaterial::GameMaterial() { ... }.  CreateMaterialResource tries to use this constructor, so your linker complains when it can't find the code for that constructor.   