comprehensive-rust/third_party/rust-on-exercism/health-statistics.rs

// ANCHOR: solution
// ANCHOR: setup

#![allow(dead_code)]
pub struct User {
    name: String,
    age: u32,
    height: f32,
    visit_count: u32,
    last_blood_pressure: Option<(u32, u32)>,
}

pub struct Measurements {
    height: f32,
    blood_pressure: (u32, u32),
}

pub struct HealthReport<'a> {
    patient_name: &'a str,
    visit_count: u32,
    height_change: f32,
    blood_pressure_change: Option<(i32, i32)>,
}

impl User {
    pub fn new(name: String, age: u32, height: f32) -> Self {
        Self { name, age, height, visit_count: 0, last_blood_pressure: None }
    }
    // ANCHOR_END: setup

    // ANCHOR: User_visit_doctor
    pub fn visit_doctor(&mut self, measurements: Measurements) -> HealthReport<'_> {
        // ANCHOR_END: User_visit_doctor
        self.visit_count += 1;
        let bp = measurements.blood_pressure;
        let report = HealthReport {
            patient_name: &self.name,
            visit_count: self.visit_count,
            height_change: measurements.height - self.height,
            blood_pressure_change: self
                .last_blood_pressure
                .map(|lbp| (bp.0 as i32 - lbp.0 as i32, bp.1 as i32 - lbp.1 as i32)),
        };
        self.height = measurements.height;
        self.last_blood_pressure = Some(bp);
        report
    }
}

// ANCHOR: tests
#[test]
fn test_visit() {
    let mut bob = User::new(String::from("Bob"), 32, 155.2);
    assert_eq!(bob.visit_count, 0);
    let report =
        bob.visit_doctor(Measurements { height: 156.1, blood_pressure: (120, 80) });
    assert_eq!(report.patient_name, "Bob");
    assert_eq!(report.visit_count, 1);
    assert_eq!(report.blood_pressure_change, None);
    assert!((report.height_change - 0.9).abs() < 0.00001);

    let report =
        bob.visit_doctor(Measurements { height: 156.1, blood_pressure: (115, 76) });

    assert_eq!(report.visit_count, 2);
    assert_eq!(report.blood_pressure_change, Some((-5, -4)));
    assert_eq!(report.height_change, 0.0);
}
// ANCHOR_END: tests