Print a string from a pointer to its member class - c++

Question

So I'm trying to print a string, but I get no output. However the other values in the class prints just fine.
In main I have a for loop that prints the the values for the Skill class. In Skill I have a pointer to the Ability class.
class Skill {
private:
Ability* ability;
public:
Ability* GetAbility() {
return ability;
};
}
It gets assigned in the constructor like this:
Skill::Skill(Ability* ability){
this->ability = ability;
}
The Ability class contains just a Name and a score.
class Ability {
private:
string name;
float score;
public:
Ability(string name, float score) {
this->name = name;
this->score = score;
};
string Name() { return name; }
float GetScore() { return score; }
};
Now in main I create a few skills and assign an ability to it. as is a container class that initializes a few ablities in a vector and I can get an ability based on its name.
Skill s* = new Skill[2]
s[0] = Skill(&as.GetAbility("Strength"));
s[1] = Skill(&as.GetAbility("Charisma"));
And then we print
cout << s[i].GetAbility()->Name() << " " << s[i].GetAbility()->GetScore();
However the only output I get is the score. No name what so ever and I can't figure it out. I've tried a few things, but still noting is printing. I'm sure I'm missing something simple that will make me facepalm, but in my defense I haven't written C++ in over 10 years. Thanks in advance.
EDIT: as.GetAbility looks like this:
Ability AbilityScores::GetAbility(string abilityName) {
for (int i = 0; i < abilityScores.size(); i++) {
if (abilityScores[i].Name() == abilityName) {
return abilityScores[i];
}
}
return Ability();
}
abilityScores is a vector

Answer 1

Your AbilityScores::GetAbility() method is returning an Ability object by value, which means it returns a copy of the source Ability, and so your Skill objects will end up holding dangling pointers to temporary Ability objects that have been destroyed immediately after the Skill constructor exits. So your code has undefined behavior.
AbilityScores::GetAbility() needs to return the Ability object by reference instead:
Ability& AbilityScores::GetAbility(string abilityName) {
for (int i = 0; i < abilityScores.size(); i++) {
if (abilityScores[i].Name() == abilityName) {
return abilityScores[i];
}
}
throw ...; // there is nothing to return!
}
...
Skill s* = new Skill[2];
s[0] = Skill(&as.GetAbility("Strength"));
s[1] = Skill(&as.GetAbility("Charisma"));
...
If you want to return a default Ability when the abilityName is not found, consider using std::map instead of std::vector:
private:
std::map<std::string, Ability> abilityScores;
AbilityScores::AbilityScores() {
abilityScores["Strength"] = Ability("Strength", ...);
abilityScores["Charisma"] = Ability("Charisma", ...);
...
}
Ability& AbilityScores::GetAbility(string abilityName) {
// if you don't mind Name() returning "" for unknown abilities...
return abilityScores[abilityName];
// otherwise...
auto iter = abilityScores.find(abilityName);
if (iter == abilityScores.end()) {
iter = abilityScores.emplace(abilityName, 0.0f).first;
}
return iter->second;
}
...
Skill s* = new Skill[2];
s[0] = Skill(&as.GetAbility("Strength"));
s[1] = Skill(&as.GetAbility("Charisma"));
...
Otherwise, return the Ability object by pointer instead:
Ability* AbilityScores::GetAbility(string abilityName) {
for (int i = 0; i < abilityScores.size(); i++) {
if (abilityScores[i].Name() == abilityName) {
return &abilityScores[i];
}
}
return nullptr;
// or:
abilityScores.emplace_back(abilityName, 0.0f);
return &(abilityScores.back());
}
...
Skill s* = new Skill[2];
s[0] = Skill(as.GetAbility("Strength"));
s[1] = Skill(as.GetAbility("Charisma"));
...