Programming Help

Web Development

What's Here?

Members: 109,554
Replies: 414,456
Topics: 63,026
Snippets: 2,288
Tutorials: 611
Total Online: 1,330
Members: 60
Guests: 1,270

C and C++

Welcome to Dream.In.Code
	Getting C++ Help is Easy! Join 109,554 C++ Programmers for FREE! Ask your question and get quick answers from experts. There are 1,330 online right now! We've got more than 500 tutorials and 2,000 snippets. Join and find out why Dream.In.Code is the #1 programming help community on the internet! Registration is fast and FREE... Join Now! Chat LIVE With a C++ Expert Register to Make This Box Go Away!

constructor with a reference paramater

constructor with a reference paramater

Options

B.H.S.	6 Aug, 2008 - 11:19 PM Post #1
New D.I.C Head Joined: 4 Aug, 2008 Posts: 1	Hello, If I need to have a constructor with a reference paramater. How should I write it? class A{ A(float &, int); // my c'tor }; I have to make sure that no one will write: A(2.4,1); or ... double s = 3.0l; A(s,1); ... Thanks Helen
	This Post Was Helpful! ^New!

Register for Free to Make This Ad Go Away!

KYA

7 Aug, 2008 - 07:35 AM

Post #2

#include <nerd.h>

Joined: 14 Sep, 2007
Posts: 2,932

Windows

Thanked 22 times

Dream Kudos: 1150
My Contributions

That's how i would write it. Outside the class you would have to have some sort of checking mechanism for the variable before you pass a reference of it to the class.

i.e.

cpp


//Reference.h file
#ifndef REFERENCE_H
#define REFERENCE_H

class Boy
{
public:
	Boy(int&);//takes reference as parameter
	~Boy();
	int itsAge;
};

Boy::Boy(int& age)
{
	itsAge = age;
}

Boy::~Boy()
{
}
#endif

And:

cpp


//main.cpp file
#include <iostream>
#include "Reference.h"
using namespace std;

int main()
{
	//verify variable type or such here
	int age = 5;
	Boy theGuy(age);
	cout << "The boy is: " << theGuy.itsAge << " years old!";
	return 0;
}

This Post Was Helpful! ^New!

Bench	7 Aug, 2008 - 11:01 AM Post #3
D.I.C Addict Joined: 20 Aug, 2007 Posts: 580 Thanked 4 times Dream Kudos: 150 Expert In: C/C++ My Contributions	If you're writing a constructor which accepts arguments by-reference, then the safest way would be to pass by const reference, unless you need to modify the original variables. cpp class myclass ( public: myclass ( const int& , const double& ); ); The reason this is preferable, is to allow const variables to be passed to the constructor - the const qualifier provides the compiler a solid guarantee that the constructor cannot produce any modifying 'side effects' to the original variables, helping keep your code cleaner, and easier to follow.
	This Post Was Helpful! ^New!