Help with error C2082: redefinition of formal parameter

Question

0.00/5 (No votes)

See more:

My code below has error C2082: redefinition of formal parameter 'm':

C++

class A {
protected:
	float Ra;
public:
	A(float a=0);
};

A::A(float a) {
	Ra = a;
}

class B: public A {
public:
	B(float r=0);
};

B::B(float r) {
	A(r); // here, I called the constructor of base class (class A)
}

Then I tried to add one more argument to the constructor of base class (class A). And in the constructor of class B, I called the constructor of class A and it worked (no error). Could anyone please tell me why?

C++

class A {
protected:
    float Ra, Rb;
public:
    A(float a=0, float b=0); // additional argument: float b
};
 
A::A(float a, float B) {
    Ra=a;
    Rb=b;
}
 
class B: public A {
public:
    B(float r=0);
};
 
B::B(float r) {
    A(r,r); // here, I called the constructor of base class (class A)
}

Posted 18-Dec-11 23:41pm

voanhkhach

Add a Solution

Comments

ARopo 19-Dec-11 5:54am

Can't see any reason for this in the code provied , where is m the error refers to parameter m

3 solutions

Solution 3

Thanks very much for your solutions but I really want to know how the compiler worked! Thanks again :)

Posted 19-Dec-11 0:54am

voanhkhach

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

CPallini · Accepted Answer · 2011-12-19T00:18:00

Solution 1

In the first case the compiler assumes A(r) is the functional syntax of the cast operator. You have to replace A(r) with A::A(r), as in

C++

B::B(float r)
{
  A::A(r)
}

or do what we, 'standard humans', usually do

C++

B::B(float r) : A(r) 
{
}

Posted 19-Dec-11 0:18am

CPallini

Comments

Timberbird 19-Dec-11 6:28am

Oh I see. Forgout about cast in my solution

Timberbird · Accepted Answer · 2011-12-19T00:26:00

If you want to call base class constructor, you should do it this way:

C++

B::B(float r) : A(r) {
...
}

I'm not sure what causes an error in your first example, but I can assume that compiler treats

C++

B::B(float r) {
	A(r); 
}

as an attempt to initialize new variable r of type A. This variable name conflicts with constructor's argument name, and thus you get an error of parameter redefinition (float r being redefined as A r)