access a member of class using vector - c++

Question

I have a class defined as
typedef std::string Name;
typedef int Age;
typedef std::string Level;
class Employee
{
public:
// Employee (arguments);
// virtual ~Employee ();
void name(Name const & name) { name_ = name; }
Name name() const { return name_; }
void age(Age const & age) { age_ = age; }
Age age() const { return age_; }
void level(Level const & level) { level_ = level; }
Level level() const { return level_; }
private:
Name name_;
Age age_;
Level level_;
};
std::vector<Employee> read_file(std::string filename);
std::vector<Employee> employees = read_file("data.txt");
std::cout << employees.size() << std:: endl;
for(std::vector<Employee>::iterator it = employees.begin(); it != employees.end(); ++it)
{
std::cout << *it << std::endl;
}
Is there a way for me to access the members of the class Employee using this vector defined above? I want to construct a map container with level of the employee as the key value.

Answer 1

If you want to access members of Employee from the iterator you can use the member access operator ->:
the_map[it->level()] = blah;

Answer 2

Unless I'm misinterpreting your question, this is simple enough.
it is an iterator over the vector of Employee.
*it is the Employee
it-> lets you access members of that Employee
e.g.: it->name()
So, if you want to build a map of employee level to Employee, you can do this:
std::map<Level, Employee> employeeMap;
for(std::vector<Employee>::iterator it = employees.begin();
it != employees.end();
++it)
{
employeeMap[ it->level() ] = *it;
}
Now you have your employeeMap, which maps the employee's Level to the Employee

Answer 3

const Name name = it->name();
const Age age = it->age();
const Level level = it->level();
or
const Name name = employees[i].name();
const Age age = employees[i].age();
const Level level = employees[i].level();
will work fine.
I would, however, strongly recommend you return each of the above items as references as it will generally be a lot faster than making a copy of the object.
ie
class Employee
{
public:
// Employee (arguments);
// virtual ~Employee ();
void name(Name const & name) { name_ = name; }
Name& name() { return name_; }
const Name& name() const { return name_; }
void age(Age const & age) { age_ = age; }
Age& age() { return age_; }
const Age& age() const { return age_; }
void level(Level const & level) { level_ = level; }
Level& level() { return level_; }
const Level& level() const { return level_; }
private:
Name name_;
Age age_;
Level level_;
};
Then you can access the values by reference as follows:
const Name& name = it->name();
const Age& age = it->age();
const Level& level = it->level();
It also means you can change the values like this:
it->name() = "Goz";
it->age() = 33;
it->level() = "Programmer";