Function Return in Rust 1.55

In Rust, we use the return keyword to return a value from a method or function.

Here's an example function that takes two integers as input and returns their sum:

fn add(a: i32, b: i32) -> i32 {
    let sum = a + b;
    return sum;
}

In this example, the add() function takes two arguments a and b, both of type i32 (32-bit integer). Inside the function, we create a new variable sum by adding a and b together.

Finally, we use the return keyword to return the value of sum back to the caller.

To call this function and get the result, we can use the following code:

fn main() {
    let result = add(10, 20);
    println!("Result: {}", result); // Output: Result: 30
}

This code declares a new variable result and assigns to it the value returned by calling the add() function with arguments 10 and 20. We then use println!() macro to display the result.

We can also omit the return keyword and let Rust implicitly return the value of the last expression in a function:

fn subtract(a: i32, b: i32) -> i32 {
    let difference = a - b;
    difference // Implicit return
}

Here, subtract() function takes two arguments a and b, both of type i32. Inside the function, we create a new variable difference by subtracting b from a.

We don't need to use return keyword in this case because the last line of the function difference is an expression that Rust implicitly returns the value of.

To call this function and get the result, we can use the following code:

fn main() {
    let result = subtract(30, 12);
    println!("Result: {}", result); // Output: Result: 18
}

This code declares a new variable result and assigns to it the value returned by calling the subtract() function with arguments 30 and 12. We then use println!() macro to display the result.