Problem with constructors and including headers

Question

I guess this can be a conceptual problem, but I couldn't find anything to solve it. I'm new to C++, and I'm having troubles with the includes (i'm working in Visual Studio 2017 on Windows 10). I've created these classes:

Shader
Material
Mesh

Each one of them with their .h and .cpp files respectively. The .h of each one of them looks like this:

Shader.h

#pragma once
class Shader
{
public:
    //Default constructor
private:
    //Some stuff
}

Material.h

#pragma once
#include "Shader.h"

class Material
{
public:
    Material(Shader s);
private:
    //Some stuff
}

Mesh.h

#pragma once
#include "Material.h"

class Mesh
{
public:
    Mesh(Material m);
private:
    //Some stuff
}

The problem appears in Mesh.cpp, when I write this:

Mesh.cpp

#include "stdafx.h"
#include "Mesh.h"

Mesh::Mesh(Material mat)
{

}

If I write that, Visual Studio gives me this error (marking in red the first bracket of the constructor):

No default constructor exists for class "Material"

Why is it assuming that I'm defining Material class constructor only by including Material.h in the header of Mesh class? Another problem appears if I just remove the constructor and try to create an object of type Mesh in, for example, Main.cpp. If I do this (letting Mesh with default constructor):

Mesh m = Mesh();

The compiler says:

The default constructor of Mesh::Mesh cannot be referenced - - it is a deleted function

I don't know what to do or what to search for. Hope I gave you the necessary information to help me, thanks in advance!

related/dupe: https://stackoverflow.com/questions/14219242/default-constructor-missing-but-im-not-calling-it — NathanOliver, Feb 28 '19 at 17:34
As soon you do this `Mesh(Material m);` the default constructor is deleted by the compiler automatically. Copy constructors and assignment operators are strill generated as usual. — πάντα ῥεῖ, Feb 28 '19 at 17:34
`Mesh() = default;` - *iff* the compiler generated default constructor works for your purposes. — Jesper Juhl, Feb 28 '19 at 17:42

score 1 · Accepted Answer · answered Feb 28 '19 at 18:18

1

It sounds like you’ve left something out of your sample code. The class Mesh has a data member of type Material, doesn’t it? Material doesn’t have a default constructor, so every constructor for Mesh has to explicitly initialize the Material member.

Mesh::Mesh(Material mat)
{ // no initializer for Material data member
)

Add an initializer list. Assuming the data member is named m, the constructor should look like this:

Mesh::Mesh(Material mat)
: m(mat) // initializes m
{
}

answered Feb 28 '19 at 18:18

Pete Becker

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It does have a member variable of type Material, yes. So, if the constructor is only used to pass the 'Material' object, I'd have to add your code and leave the body empty? – Raúl Cuadrado Feb 28 '19 at 19:12

Problem with constructors and including headers

1 Answers1