Alright I got some errors after changing it to const.

Battle_M.obj : error LNK2019: unresolved external symbol "public: class Lifeform & __thiscall Lifeform::operator=(class Lifeform const &)" (??4Lifeform@@QAEAAV0@ABV0@@Z) referenced in function "public: class FieldSquare & __thiscall FieldSquare::operator=(class FieldSquare const &)" (??4FieldSquare@@QAEAAV0@ABV0@@Z)

FieldSquare_M.obj : error LNK2019: unresolved external symbol "public: class Lifeform & __thiscall Lifeform::operator=(class Lifeform &)" (??4Lifeform@@QAEAAV0@AAV0@@Z) referenced in function "public: void __thiscall FieldSquare::setOccupant(class Lifeform &)" (?setOccupant@FieldSquare@@QAEXAAVLifeform@@@Z)

Goblin_M.obj : error LNK2019: unresolved external symbol "public: class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __thiscall Lifeform::getName(void)" (?getName@Lifeform@@QAE?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ) referenced in function "public: class Goblin & __thiscall Goblin::operator=(class Goblin &)" (??4Goblin@@QAEAAV0@AAV0@@Z)
Debug/grid slayers.exe : fatal error LNK1120: 3 unresolved externals



Now my stats and skills are held in maps. I tried making them const but I got this.

error C2678: binary '[' : no operator found which takes a left-hand operand of type 'const std::map<_Kty,_Ty>' (or there is no acceptable conversion)
with
[
_Kty=std::string,
_Ty=int
]


Here is my getStat function

int Lifeform::getStat(string stat) const
{
if ( stats.find(stat) != stats.end() )
return stats[stat];
else
{
cout << "I couldn't find that stat in the stats map" << endl;
return 0;
}
}

getSkills is very similar just with skills.

Quote:Original post by Magmai Kai Holmlor
const Lifeform& Lifeform::operator=(const Lifeform& copy_me)

assignment operators should return non-constant reference.

@Grahf750 this his how all your assignment operators should take the form of:

foo& operator=(const foo&);

Also like said a twice already you do not need to explicitly define assignment operators & copy constructors as they are implicitly defined (compiler generated) by default to do a member-wise copy/assign. Yes it will still work with std::basic_string as it does the correct behaviour with the default, its not a pointer.

Original post by Grahf750
Now my stats and skills are held in maps. I tried making them const but I got this.

error C2678: binary '[' : no operator found which takes a left-hand operand of type 'const std::map<_Kty,_Ty>' (or there is no acceptable conversion)
with
[
_Kty=std::string,
_Ty=int
]


Here is my getStat function

int Lifeform::getStat(string stat) const
{
if ( stats.find(stat) != stats.end() )
return stats[stat];
else {
cout

struct Lifeform {
typedef std::map mmap;
//.....
};
///...

int Lifeform::getStat(const string& stat) const {

mmap::const_iterator itr = stats.find(stat);
if (itr != stats.end() )
return itr->second;
else {
cerr

2. Making std::map a mutable member:


struct Lifeform {

typedef std::map mmap;

private:

mutable mmap my_map;

};


Always prefer the former.

... again i was logged out for no reason what so ever so the above post was me and for some reason has stuff i wrote missing.

Quote:Original post by Magmai Kai Holmlor
const Lifeform& Lifeform::operator=(const Lifeform& copy_me)

assignment operators should return non-constant reference.

@Grahf750 this his how all your assignment operators should take the form of:

foo& operator=(const foo&);

Also like said twice already you do not need to explicitly define assignment operators & copy constructors as they are implicitly defined (compiler generated) by default to do a member-wise copy/assign. Yes it will still work with std::basic_string as it does the correct behaviour with the default, its not a pointer.

Quote:Original post by Grahf750
Now my stats and skills are held in maps. I tried making them const but I got this.

error C2678: binary '[' : no operator found which takes a left-hand operand of type 'const std::map<_Kty,_Ty>' (or there is no acceptable conversion)
with
[
_Kty=std::string,
_Ty=int
]


Here is my getStat function

int Lifeform::getStat(string stat) const
{
if ( stats.find(stat) != stats.end() )
return stats[stat];
else
{
cout << "I couldn't find that stat in the stats map" << endl;
return 0;
}
}

getSkills is very similar just with skills.

That is an issue with std::map's subscript operator and using it inside a constant member functions, you have two solutions:

1. Using Constant Iterators.

struct Lifeform {   typedef std::map mmap;   //.....};///...int Lifeform::getStat(const string& stat) const {   mmap::const_iterator itr = stats.find(stat);   if (itr  != stats.end() )      return itr->second;   else {      cerr << "I couldn't find that stat in the stats map" << endl;      return 0;    }}

2. Making std::map a mutable member:

struct Lifeform {   typedef std::map mmap;   private:   mutable mmap my_map;};

Always prefer the former.

The problem here is that when you do:

mmap::const_iterator itr = stats.find(stat);

it says error C2678: binary '=' : no operator found which takes a left-hand operand of type 'const std::map<_Kty,_Ty>::iterator' (or there is no acceptable conversion)

Quote:Original post by Grahf750
The problem here is that when you do:

mmap::const_iterator itr = stats.find(stat);

it says error C2678: binary '=' : no operator found which takes a left-hand operand of type 'const std::map<_Kty,_Ty>::iterator' (or there is no acceptable conversion)

Hmm well i tested it out on VC++ 7.1 (that appears to be what your using) and its work fine but that error looks suspicious to me you should know that:

const std::map::iterator != std::map::const_iterator

Meaning they are not the same type.

Alright yeh fixed that I misread what you put and thought the const_Iterator was the name of the const iterator that is just stupid blindness on my part. You would think I would wonder because I never made it const lol. So that works fine.

I am all good now so thanks for the help all and especially you snk_kid.

I still got this error though and I have not explicitely defined the = operator anymore as you said.(Please read paragraph after error)

Info: I store a lifeform in the fieldSquare class


Battle_M.obj : error LNK2019: unresolved external symbol "public: class Lifeform const & __thiscall Lifeform::operator=(class Lifeform const &)" (??4Lifeform@@QAEABV0@ABV0@@Z) referenced in function "public: class FieldSquare & __thiscall FieldSquare::operator=(class FieldSquare const &)" (??4FieldSquare@@QAEAAV0@ABV0@@Z)

FieldSquare_M.obj : error LNK2001: unresolved external symbol "public: class Lifeform const & __thiscall Lifeform::operator=(class Lifeform const &)" (??4Lifeform@@QAEABV0@ABV0@@Z)

Debug/grid slayers.exe : fatal error LNK1120: 1 unresolved externals


Now I commented some stuff out in the field square class dealing with the lifeform. Just the set and get methods and when I uncommented it and tried compiling again it worked. I have tested it and it works fine I find this strange anybody have any explanation? Maybe it wasn't recompiling or just comfused I have had that happend before where restarting visual studio makes it work.