Operator overloading doesn't work

Question

I'm making a matrix3x3 class, and although I have the required functionality thereof the operator overloading as to *=, +=, -= and /= don't work. Here's what I have:

mat3 operator*(const mat3 &m); // Declared within mat3 class

mat3 mat3::operator *=(const mat3& m) // How it's implemented
{
    *this = *this * m;
    return *this;
}

Suffice it to say, that it kinda works; but this is the usage I want:

mat3 m; // Initialise to identity matrix

m *= mat3(2.0); // Multiply matrix by scalar and apply

The problem is that it doesn't affect the matrix at all! m remains the same, even though I've just done a *= mat3(2.0) operation on it. However, this works:

m = m *= mat3(2.0);

Which is just silly, because I might as well do:

m = m * mat3(2.0);

The whole point is that all the above multiplications MUST return the same result. There's no approximations nor compromise here. Quite frankly, all the operators pertaining to *=, += etc do not work. How can I get this kind of operator overload working such that multiplying a matrix and applying that multiplication can be done as easy as:

m *= mat3(2.0)

write operator * in terms of operator *=. You've got it the wrong way around. — Richard Hodges, Dec 15 '15 at 23:37
Think of what this returns: `mat3 mat3::operator *=(const mat3& m)`. Then read http://stackoverflow.com/questions/4421706/operator-overloading — juanchopanza, Dec 15 '15 at 23:37
Your `operator*=` looks fine (though it would be better to return by reference). The problem must be in some code not shown here. — aschepler, Dec 15 '15 at 23:57
@RichardHodges I don't think that advice applies to matrix multiplication, which is not easily done "in place". — aschepler, Dec 15 '15 at 23:59
`m *= 2;` shouldn't compile unless you have a converting constructor, which seems nonsensical. — molbdnilo, Dec 15 '15 at 23:59
I'd guess that your copy-assignment operator or copy-constructor is not implemented properly. To get good answers, post a [MCVE](http://stackoverflow.com/help/mcve) — M.M, Dec 16 '15 at 00:00
Change the return type `mat3& mat3::operator *=(const mat3& m)` — Danh, Dec 16 '15 at 00:04
Thanks everyone. I think I solved the issue. I don't know how I solved it, but I know I didn't use a screw driver this time! — Poriferous, Dec 16 '15 at 00:09

Operator overloading doesn't work

0 Answers0