Rust Function: Square root calculation

Rust Result and Option types: Exercise-4 with Solution

Write a Rust function that calculates the square root of a non-negative number and returns Option<f64>, where None is returned for negative inputs.

Sample Solution:

Rust Code:

// Define a function called calculate_square_root that takes a parameter x of type f64 and returns an Option<f64>
fn calculate_square_root(x: f64) -> Option<f64> {
    // Check if the input x is non-negative
    if x >= 0.0 {
        // If x is non-negative, calculate its square root using sqrt() method and wrap the result in Some
        Some(x.sqrt())
    } else {
        // If x is negative, return None
        None
    }
}

// Define the main function
fn main() {
    // Define a variable x and assign it a non-negative value
    let x = 225.0;
    // Match the result of calculate_square_root function with pattern matching
    match calculate_square_root(x) {
        // If calculate_square_root returns Some(result), print the square root
        Some(result) => println!("Square root of {} is {}", x, result),
        // If calculate_square_root returns None, print an error message
        None => println!("Cannot calculate square root of a negative number"),
    }
}

Output:

Square root of 225 is 15

Explanation:

Here's a brief explanation of the above Rust code:

• Function calculate_square_root(x: f64) -> Option<f64>:
• This function takes a parameter 'x' of type 'f64' (64-bit floating-point number) and returns an Option<f64>.
• It checks if the input 'x' is non-negative. If it is, it calculates the square root of 'x' using the 'sqrt()' method and returns it wrapped in 'Some'. If 'x' is negative, it returns 'None'.
• Main Function:
• In the "main()" function, a variable 'x' is defined and assigned a non-negative value (225.0 in this case).
• The calculate_square_root function is called with 'x' as an argument.
• The result of "calculate_square_root()" is matched using pattern matching (match):
• If the result is 'Some(result)', meaning the square root was successfully calculated, it prints the square root.
• If the result is 'None', indicating that the input number was negative, it prints an error message indicating that the square root cannot be calculated for negative numbers.

Rust Code Editor:

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