c++ problems :/

[titi]

Hi, I have a little problem with typedefs:

in skill_type.h I want to define this:

Code: [Select]

typedef list<UnitParticleSystemType*> UnitParticleSystemTypes;
// =====================================================
// class SkillType
//
/// A basic action that an unit can perform
// =====================================================

class SkillType{

   
protected:
    SkillClass skillClass;
string name;
int mpCost;
    int speed;
    int animSpeed;
    Model *animation;
    SoundContainer sounds;
float soundStartTime;
public:
UnitParticleSystemTypes unitParticleSystemTypes;

....
and in unit.cpp I want to use the type "UnitParticleSystemTypes" like this:

Code: [Select]

if((!currSkill->unitParticleSystemTypes.empty())
&& (unitParticleSystems.empty()) ){
for(UnitParticleSystemTypes::iterator it= currSkill->unitParticleSystemTypes.begin(); it!=currSkill->unitParticleSystemTypes.end(); ++it){
UnitParticleSystem *ups;
ups= new UnitParticleSystem(200);
(*it)->setValues(ups);
ups->setPos(getCurrVector());
ups->setTeamNumber(getTeam());
unitParticleSystems.push_back(ups);
Renderer::getInstance().manageParticleSystem(ups, rsGame);
}
}

I get an error in this line :
for(UnitParticleSystemTypes::iterator it= currSkill->unitParticleSystemTypes.begin();it!=currSkill->unitParticleSystemTypes.end(); ++it){
...

saying

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C++ ./build/i686-pc-linux-gnu/optimize/glest_game/type_instances/unit.o
glest_game/type_instances/unit.cpp: In member function 'void Glest::Game::Unit::setCurrSkill(const Glest::Game::SkillType*)':
glest_game/type_instances/unit.cpp:324: error: conversion from 'std::_List_const_iterator<Glest::Game::UnitParticleSystemType*>' to non-scalar type 'std::_List_iterator<Glest::Game::UnitParticleSystemType*>' requested

Whats wrong? how can I fix it?

[Yggdrasil]

Use const_iterator instead of iterator.

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for(UnitParticleSystemTypes::const_iterator it=...


[silnarm]

That will get rid of that error...

However, it will probably create a new one on,
(*it)->setValues(ups);
unless UnitParticleSystemType::setValues() is const, and with a name like that, I doubt it is!

Hacky fix,

Code: [Select]

UnitParticleSystemType *upst = const_cast<UnitParticleSystemType*>(*it);
upst->setValues(ups);

Edit:  Actually, only the pointer will be const, not what's pointed to, so just do what Yggdrasil said, you don't need this hack

[titi]

done
Thanks its working perfectly now ( already checked in in megaglest now )
It may be a dumb question, but whats the difference of const_iterator and  iterator?

[silnarm]

With a const_iterator you can't modify what it references, if you have a const collection class, you must use a const_iterator, or if you are in a const method, then any members (including any collection classes) may not be modified, so again, you must use a const_iterator.