My code will not run no matter what I change, and I’m not sure what this error actually means. I just started this class so I have to use clion, which I am fairly new to. This is cloned from github to clion.

Tried to compile my code and I keep getting this error:

Undefined symbols for architecture arm64:
  "getPosition(Particle const*)", referenced from:
      (anonymous namespace)::ParticleFixture_TestGetPosition_Test::TestBody() in particle_unittest.cc.o
      (anonymous namespace)::ParticleFixture_TestGetPosition_Test::TestBody() in particle_unittest.cc.o
  "moveCoord3D(Coord3D*, Coord3D const*, double)", referenced from:
      (anonymous namespace)::ParticleFixture_TestMoveCoord3D_Test::TestBody() in particle_unittest.cc.o
      (anonymous namespace)::ParticleFixture_TestMoveCoord3D_Test::TestBody() in particle_unittest.cc.o
      (anonymous namespace)::ParticleFixture_TestMoveCoord3D_Test::TestBody() in particle_unittest.cc.o
  "deleteParticle(Particle const*)", referenced from:
      (anonymous namespace)::ParticleFixture_TestCreateDeleteParticle_Test::TestBody() in particle_unittest.cc.o
      (anonymous namespace)::ParticleFixture_TestCreateDeleteParticle_Test::TestBody() in particle_unittest.cc.o
      (anonymous namespace)::ParticleFixture_TestGetPosition_Test::TestBody() in particle_unittest.cc.o
      (anonymous namespace)::ParticleFixture_TestGetPosition_Test::TestBody() in particle_unittest.cc.o
      (anonymous namespace)::ParticleFixture_TestMoveParticle_Test::TestBody() in particle_unittest.cc.o
      (anonymous namespace)::ParticleFixture_TestSetVelocity_Test::TestBody() in particle_unittest.cc.o
  "length(Coord3D const*)", referenced from:
      (anonymous namespace)::ParticleFixture_TestLength_Test::TestBody() in particle_unittest.cc.o
      (anonymous namespace)::ParticleFixture_TestLength_Test::TestBody() in particle_unittest.cc.o
      (anonymous namespace)::ParticleFixture_TestLength_Test::TestBody() in particle_unittest.cc.o
      (anonymous namespace)::ParticleFixture_TestLength_Test::TestBody() in particle_unittest.cc.o
  "Particle::_num_allocations", referenced from:
      Particle::getNumAllocations() in particle_unittest.cc.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
ninja: build stopped: subcommand failed.

This is my code.

main.cc

int main() {
    Coord3D pointP = {10, 20, 30};
    Coord3D pointQ = {-20, 21, -22};

    std::cout << "Address of P: " << &pointP << std::endl;
    std::cout << "Address of Q: " << &pointQ << std::endl << std::endl;

    Coord3D *ans = fartherFromOrigin(&pointP, &pointQ);

    std::cout << "ans = " << ans << std::endl; // So which point is farther?

    //task c

    Coord3D pos = {0, 0, 100.0};
    Coord3D vel = {1, -5, 0.2};

    std::cout << "Initial position: " << pos.x << " " << pos.y << " " << pos.z << std::endl;

    moveCoord3D(&pos, &vel, 2.0); // object pos gets changed

    std::cout << "New position: " << pos.x << " " << pos.y << " " << pos.z << std::endl;
    // prints: 2 -10 100.4
    // task D

    double x, y, z;
    std::cout << "Enter position: ";
    std::cin >> x >> y >> z;
    Coord3D *ppos = createCoord3D(x, y, z);

    std::cout << "Enter velocity: ";
    std::cin >> x >> y >> z;
    Coord3D *pvel = createCoord3D(x, y, z);

    moveCoord3D(ppos, pvel, 10.0);

    std::cout << "Coordinates after 10 seconds: "
         << (*ppos).x << " " << (*ppos).y << " " << (*ppos).z << std::endl;

    deleteCoord3D(ppos); // release memory
    deleteCoord3D(pvel);

    //task E
    Particle *p = createParticle(1.0, 1.5, 2.0, 0.1, 0.2, 0.3);
    double time = 0.0;
    double dt = 0.1;
    while(time < 3.0) {
        setVelocity(p, 10.0 * time, 0.3, 0.1);
        moveParticle(p, dt);
        time += dt;
        std::cout << "Time: " << time << " t";
        std::cout << "Position: "
             << getPosition(p).x << ", "
             << getPosition(p).y << ", "
             << getPosition(p).z << std::endl;
    }
    deleteParticle(p);
    return EXIT_SUCCESS;
}

Particle.cc

#include <iostream>
#include <cmath>

class Coord3D {
public:
    double x;
    double y;
    double z;
};



double length(Coord3D *p) {
    // Dereference the pointer to access x, y, z coordinates
    double x = p->x;
    double y = p->y;
    double z = p->z;
    // Compute the distance using the Euclidean distance formula
    double distance = sqrt(x * x + y * y + z * z);
    return distance;
}

Coord3D *fartherFromOrigin(Coord3D *p1, Coord3D *p2) {
    if (length(p1) > length(p2)) {
        return p1;
    } else {
        return p2;
    }
}

Coord3D* createCoord3D(double x, double y, double z) {
    Coord3D *p = new Coord3D;
    p->x = x;
    p->y = y;
    p->z = z;
    return p;
}

void deleteCoord3D(Coord3D *p) {
    delete p;
}

void moveCoord3D(Coord3D *ppos, Coord3D *pvel, double dt) {
    ppos->x += pvel->x * dt;
    ppos->y += pvel->y * dt;
    ppos->z += pvel->z * dt;
}

struct Particle {
    Coord3D pos;
    Coord3D vel;
};

Particle* createParticle(double x, double y, double z, double vx, double vy, double vz) {
    Particle *p = new Particle;
    p->pos.x = x;
    p->pos.y = y;
    p->pos.z = z;
    p->vel.x = vx;
    p->vel.y = vy;
    p->vel.z = vz;
    return p;
}

void setVelocity(Particle *p, double vx, double vy, double vz) {
    p->vel.x = vx;
    p->vel.y = vy;
    p->vel.z = vz;
}

Coord3D getPosition(Particle *p);

Coord3D getPosition(Particle *p) {
    return p->pos;
}

void moveParticle(Particle *p, double dt) {
    p->pos.x += p->vel.x * dt;
    p->pos.y += p->vel.y * dt;
    p->pos.z += p->vel.z * dt;
}

void deleteParticle(Particle *p) {
    delete p;
}

Particle.h

#ifndef PARTICLE_H
#define PARTICLE_H

#include <cstdlib>

struct Coord3D {
    double x;
    double y;
    double z;
};

// get the distance from the given coordinate to the origin
double length(const Coord3D* p);

// return the coordinate that's farthest from the origin
Coord3D* fartherFromOrigin(Coord3D* p1, Coord3D* p2);

// advance the position of the coordinate traveling at a given speed for a
// given time
void moveCoord3D(Coord3D* ppos, const Coord3D* pvel, double dt);

struct Particle {
public:
    double x;
    double y;
    double z;
    double vx;
    double vy;
    double vz;

    static size_t getNumAllocations() { return _num_allocations; }

    void* operator new(const size_t t) {
        (void)t;
        _num_allocations++;
        return ::new Particle();
    }

    void operator delete(void *const p) {
        _num_allocations--;
        free(p);
    }

private:
    static size_t _num_allocations;
};

// dynamically allocate memory for a particle and initialize it
Particle* createParticle(double x, double y, double z,
                         double vx, double vy, double vz);

// set its velocity to (vx, vy, vz)
void setVelocity(Particle* p, double vx, double vy, double vz);

// get its current position
Coord3D getPosition(const Particle* p);

// update particle's position after elapsed time dt
void moveParticle(Particle* p, double dt);

// delete all memory allocated for the particle passed by pointer
void deleteParticle(const Particle* p);

#endif // PARTICLE_H