rustUsing question mark errors in Rust

Rust uses the question mark operator (?) to handle errors in a concise and easy-to-read way. This operator is used to return a Result type, which can either be Ok or Err.

Code example:

fn main() {
    let result = divide(4, 2);
    match result {
        Ok(val) => println!("Result: {}", val),
        Err(e) => println!("Error: {}", e),
    }
}

fn divide(x: i32, y: i32) -> Result<i32, &'static str> {
    if y == 0 {
        return Err("Cannot divide by 0");
    }
    Ok(x / y)
}

Output

Result: 2

Explanation:

• fn main(): This is the main function, which is the entry point of the program.
• let result = divide(4, 2): This line calls the divide function with the arguments 4 and 2.
• match result {: This line uses a match expression to check the result of the divide function.
• Ok(val) => println!("Result: {}", val): If the result is Ok, this line prints the value of val.
• Err(e) => println!("Error: {}", e): If the result is Err, this line prints the value of e.
• fn divide(x: i32, y: i32) -> Result<i32, &'static str>: This is the divide function, which takes two i32 arguments and returns a Result type.
• if y == 0 {: This line checks if the second argument is 0.
• return Err("Cannot divide by 0"): If the second argument is 0, this line returns an Err with the message Cannot divide by 0.
• Ok(x / y): If the second argument is not 0, this line returns an Ok with the result of the division.

Helpful links:

• Rust Documentation - Error Handling
• Rust Documentation - The Question Mark Operator

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