Class has more than one constructor - c++

Question

Currently, im working on an CVector class, everything was working fine until i wanted to use vectors in other classes like CVector v; and use the v later.
well, the problem lies there - i would use
struct Vector3_t {
float x, y , z;
};
but i want to use operators for those vectors, so i made a class:
class CVector
{
public:
//missing usage: CVector vec; // for later usage in example.
CVector() // usage: CVector v();
{
this->x = 0, this->y = 0, this->z = 0;
}
CVector(const float x = 0, const float y = 0) { // usage: CVector v(1,2); // but z is always 0
this->x = x, this->y = y,this->z = 0;
}
CVector(const float x = 0, const float y = 0, const float z = 0) { // usage: CVector v(1,2,3);
this->x = x, this->y = y, this->z = z;
}
CVector & CVector::operator += (const CVector & v) {
this->x += v.x; this->y += v.y; this->z += v.z; return *this;
}
const CVector CVector::operator + (const CVector& v) const {
CVector r(*this); return r += v;
}
float x, y, z;
~CVector() {};
protected:
private:
};
in action:
int main() {
CVector vec;
return 0;
}
output errors:
Severity Code Description Project File Line Suppression State
Error (active) class "CVector" has more than one default constructor mebad c:\Users\lifesucks\Documents\Visual Studio 2015\Projects\mebad\mebad\main.cpp 43
*Severity Code Description Project File Line Suppression State
Error C2668 'CVector::CVector': ambiguous call to overloaded function mebad c:\users\lifesucks\documents\visual studio 2015\projects\mebad\mebad\main.cpp 43
*
basically i just have no idea how to declare class for this kind of use when having multiple constructors, and i dont want to use more function like CVector::constr1 which would use 3 floats or anything similiar, there must be a way to do it this way, could i get a bit of help? Thanks!

Answer 1

The problem is your use of default values for the arguments to two of the constructors, that means you have three constructors that can be called without arguments, so which should the compiler call?
Simply remove the default argument values and it should work.

Answer 2

Your class should be
class CVector
{
public:
CVector() : x(0), y(0), z(0) {}
CVector(float x) : x(x), y(0), z(0) {}
CVector(float x, float y) : x(x), y(y), z(0) {}
CVector(float x, float y, float z) : x(x), y(y), z(z) {}
//...
float x, y, z;
};
or
class CVector
{
public:
CVector(float x = 0, float y = 0, float z = 0) : x(x), y(y), z(z) {}
//...
float x, y, z;
};

Answer 3

Joachim Pileborg answered this perfectly, and deserves the points.
Here are the code changes you chould make:
CVector() // usage: CVector v();
{
this->x = 0, this->y = 0, this->z = 0;
}
CVector(const float x, const float y) { // usage: CVector v(1,2); // but z is always 0
this->x = x, this->y = y,this->z = 0;
}
CVector(const float x, const float y, const float z) { // usage: CVector v(1,2,3);
this->x = x, this->y = y, this->z = z;
}