Built-in traits and operator overloading

The Rust standard library is packed with traits, which are used all over the place. For example, there are traits for which the compiler is capable of providing a basic implementation with a #[derive] attribute, as we saw in the section on Traits:

• Comparing instances: The Eq and PartialEq trait
• Ordering instances: The Ord and PartialOrd trait
• Creating an empty instance: The Default trait
• To create a zero instance of a numeric data type: The Zero trait

The next chapter shows an example of how to implement the following three traits:

• Formatting a value using {:?}: The Debug trait, defining an fmt method
• Copy an instance: The Copy trait
• Create a duplicate instance: The Clone trait
• Computing a hash: The Hash trait
• Adding instances: The Add trait, defining an add method. The + operator is just a nice way to use add: n + m is the same as n.add(m). So if we implement the Add trait, we can use the + operator, this is called operator overloading.
  • The Add trait has the...