Rust Platform

Function Return Values

Level: intro (score: 1)

🎯 In Python, defining functions is straightforward — you write def and return values as needed.

In Rust, functions are defined with fn, have typed parameters, and declare a return type.

A few key points for Pythonistas:

• Rust functions must specify parameter and return types.
• If the last expression in the function body does not end with a semicolon, it is returned.
• You can also use the return keyword, but it’s more idiomatic to just return the last expression.

✅ Your task:

Implement the add_and_double function which:

• Takes two i32 integers a and b
• Returns an i32 equal to (a + b) * 2

This exercise introduces:

• Function parameters with explicit types
• Declaring return types
• Returning expressions without return

💡 Hint: You don’t need return here — let the final expression be the value.

Example:

assert_eq!(add_and_double(2, 3), 10);
assert_eq!(add_and_double(-1, 4), 6);