Parameter Order in Operators

1#include <iostream>
2
3struct Vector3 {
4  float x, y, z;
5};
6
7// Vector3 * int
8Vector3 operator*(const Vector3& vec, int scalar) {
9  std::cout << "Called Vector3 * int\n";
10  return Vector3{
11    vec.x * scalar, vec.y * scalar, vec.z * scalar
12  };
13}
14
15// int * Vector3
16Vector3 operator*(int scalar, const Vector3& vec) {
17  std::cout << "Called int * Vector3\n";
18  return Vector3{
19    vec.x * scalar, vec.y * scalar, vec.z * scalar
20  };
21}
22
23int main() {
24  Vector3 vec{1.0f, 2.0f, 3.0f};
25
26  // Calls first overload
27  Vector3 result1{vec * 2};  
28
29  // Calls second overload
30  Vector3 result2{2 * vec}; 
31}

1Vector3 operator*(const Vector3& vec, int scalar) {
2  return Vector3{
3    vec.x * scalar, vec.y * scalar, vec.z * scalar
4  };
5}
6
7Vector3 operator*(int scalar, const Vector3& vec) {
8  return vec * scalar;  // Reuse the other overload 
9}