clamp() with custom types

To use std::ranges::clamp() with custom types, you need to define the appropriate comparison operators for your type. The spaceship operator (<=>) provides a concise way to implement all the necessary comparison operators.

Step 1: Define the Custom Type

First, create your custom type and manually implement the spaceship operator (<=>). This will automatically provide the required comparison operators.

1#include <algorithm>
2#include <iostream>
3#include <compare>
4
5struct Player {
6  int Health;
7
8  // Spaceship operator for three-way comparison
9  std::strong_ordering operator<=>(const Player& other) const {
10    return Health <=> other.Health;
11  }
12
13  // Equality operator
14  bool operator==(const Player& other) const {
15    return Health == other.Health;
16  }
17};

Step 2: Use std::ranges::clamp()

With the comparison operators defined, you can now use std::ranges::clamp() with instances of your custom type:

1#include <algorithm>
2#include <iostream>
3
Player Struct|Show
4struct Player {/*...*/};
19
20int main() {
21  Player p1{50};
22  Player p2{100};
23  Player p3{150};
24
25  Player clampedPlayer =
26    std::ranges::clamp(p2, p1, p3);
27
28  std::cout << "Clamped Player Health: "
29    << clampedPlayer.Health;
30}

1Clamped Player Health: 100

In this example, std::ranges::clamp() ensures that the Health of p2 stays within the bounds set by p1 and p3. Since p2's Health is already within the range, it remains unchanged.

Explanation

• Define the Spaceship Operator: The Player struct has the <=> operator defined, which compares Health values using std::strong_ordering. This operator provides functionality for determining the relative ordering of Player objects.
• Define the Equality Operator: The equality operator (==) is explicitly defined to determine whether two Player objects are equal, by comparing their Health values.
• Use std::ranges::clamp(): The std::ranges::clamp() function ensures that p2's Health is clamped between p1's and p3's Health.

By implementing the necessary comparison operators, you enable std::ranges::clamp() to work with your custom types, making your code more flexible and powerful.