Using forward declarations for build in datatypes.

Posted by bdhar on Stack Overflow See other posts from Stack Overflow or by bdhar
Published on 2010-06-07T11:46:59Z Indexed on 2010/06/07 11:52 UTC
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I understand that wherever possible we shall use forward declarations instead of includes to speed up the compilation.

I have a class Person like this.

#pragma once

#include <string>

class Person
{
public:
    Person(std::string name, int age);
    std::string GetName(void) const;
    int GetAge(void) const;
private:
    std::string _name;
    int _age;
};

and a class Student like this

#pragma once

#include <string>

class Person;

class Student
{
public:
    Student(std::string name, int age, int level = 0);
    Student(const Person& person);
    std::string GetName(void) const;
    int GetAge(void) const;
    int GetLevel(void) const;
private:
    std::string _name;
    int _age;
    int _level;
};

In Student.h, I have a forward declaration class Person; to use Person in my conversion constructor. Fine. But I have done #include <string> to avoid compilation error while using std::string in the code. How to use forward declaration here to avoid the compilation error? Is it possible?

Thanks.

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