# Traits

A trait is a collection of methods.

Data types can implement traits. To do so, the methods making up the trait are defined for the data type. For example, the `felt` data type implements the `Into` trait. This allows a user to write `1.into()` to convert a felt into a u256.

In this way, traits are somewhat similar to Java interfaces and C++ abstract classes.

Because traits indicate shared behavior between data types, they are useful when writing generics.

- [Traits & Impls](https://cairo-book.github.io/ch07-02-traits-in-cairo.html)