My problem is that no matter how I change my struct’s += overload, I always get the same error:

In static member function 'static void float3::graviton(const Particle&, const Particle&)':

error: passing 'const float3' as 'this' argument discards qualifiers [-fpermissive]

p_p1.v += force;

Where the force variable is highlighted as the source of the error.

The static member function static void float3::graviton(const Particle&, const Particle&) is defined as follows:

// float3.cpp

void float3::graviton(const Particle& p_p1, const Particle& p_p2) {
    float force = Physics_G * (p_p1.m * p_p2.m) / (p_p2.p - p_p2.p).magnitudeSquared();
    p_p1.v += force;
    p_p2.v += force;
}

float3 is a struct that declares graviton as: static void graviton(const Particle& p_p1, const Particle& p_p2);

Particle is a seperate struct outside of the header or cpp file for float3 with 3 fields:

• v a float3

• m a float

• p a float3

Names prefixed with Physics_ are constants defined in another seperate header file.

magnitudeSquared is a float3 member function that returns a float.

Finally, the definition for the operator += between a float3 and a float is:

// float3.h

inline void float::operator+=(float p_scalar) {
    this->x += p_scalar;
    this->y += p_scalar;
    this->z += p_scalar;
}

I have tried many things from not returning *this with the operator function, and moving the graviton function to other places. Could anyone help me find why I still get this error?

If I am missing any required information I am happy to give more.