How to Implement the Display Trait for Complex Types

Type System

2026-04-17T12:05:42+00:00

Implement the Display trait for complex types by defining a fmt method that uses write! to format the output.

Implement the Display trait for your custom type by defining an impl block that implements std::fmt::Display and provides a fmt method using write!.

use std::fmt;

struct Pair<T> {
    x: T,
    y: T,
}

impl<T: fmt::Display> fmt::Display for Pair<T> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "({}, {})", self.x, self.y)
    }
}