Activity 11 - Error Handling by Hand

Name:

1. Convert panic to Result

#![allow(unused)]
fn main() {
// Given this function that panics:
fn safe_divide(a: i32, b: i32) -> i32 {
    if b == 0 {
        panic!("Cannot divide by zero!");
    }
    a / b
}


// Rewrite it to return a Result instead of panicking:
fn safe_divide_result(a: i32, b: i32) -> ______________ {
    // Your code here












}
}

2. Error Propagation with match

• Use this helper function to complete parse_and_double
• The helper function handles parsing and returns clear error messages

#![allow(unused)]
fn main() {
// Helper function (already written for you):
fn parse_int(input: &str) -> Result<i32, String> {
    match input.parse::<i32>() {
        Ok(num) => Ok(num),
        Err(_) => Err(format!("'{}' is not a valid number", input)),
    }
}

// Complete this function using the helper:
fn parse_and_double(input: &str) -> Result<i32, String> {
    let num = match parse_int(input) {

        ___________ => ___________,

        ___________ => ___________,
    };

    let doubled = ___________;

    _____________
}
}

3. Using the ? operator

• Rewrite the parse_and_double function using the ? operator
• Use the same helper function from problem 2

#![allow(unused)]
fn main() {
fn parse_and_double_short(input: &str) -> Result<i32, String> {
    // Your code here (should be 2-3 lines)








}
}