Rust Platform

🎯 Python's if/elif/else and match (3.10+) handle branching:

def describe_temp(celsius):
    if celsius >= 30:
        label = "Hot"
    elif celsius >= 15:
        label = "Mild"
    else:
        label = "Cold"

    match label[0]:
        case "H": return "stay inside"
        case "M": return "enjoy"
        case _:   return "bundle up"

Rust has the same constructs, but with a key difference: if and match are expressions. They return values:

let label = if celsius >= 30 {
    "Hot"
} else if celsius >= 15 {
    "Mild"
} else {
    "Cold"
};

No ternary operator needed — if itself returns a value. Python's equivalent would be label = "Hot" if celsius >= 30 else ..., but Rust's version scales to any number of branches.

match: exhaustive pattern matching

Rust's match is more powerful than Python's structural match. The compiler requires you to handle every possible case:

match label.chars().next() {
    Some('H') => "stay inside".to_string(),
    Some('M') => "enjoy".to_string(),
    _ => "bundle up".to_string(),
}

The _ wildcard catches everything else. If you forget a case, the compiler tells you — no silent fall-through, no missed branches.

Your Task

Implement grade_message(score: i32) -> String:

1. Use if/else if/else to determine the grade:
2. score >= 90 → "Excellent"
3. score >= 75 → "Good"
4. score >= 50 → "Pass"

5. Otherwise → "Fail"

6. Use match on the first character of the grade to return:

7. 'E' → "Top"
8. 'G' → "Decent"
9. 'P' → "Basic"
10. Anything else → "None"

Example

assert_eq!(grade_message(95), "Top");
assert_eq!(grade_message(78), "Decent");
assert_eq!(grade_message(52), "Basic");
assert_eq!(grade_message(10), "None");

Further Reading

• The Rust Book — Control Flow — if expressions, loops
• The Rust Book — The match Control Flow — exhaustive pattern matching