Rust Function: Hex string to integer

Rust Result and Option types: Exercise-7 with Solution

Write a Rust function that converts a hexadecimal string to an integer and returns Option, returning None for invalid input.

Sample Solution:

Rust Code:

fn hex_string_to_int(hex_string: &str) -> Option<u64> {
    // Attempt to parse the hexadecimal string into a u64 integer
    match u64::from_str_radix(hex_string, 16) {
        // If parsing succeeds, return the parsed integer wrapped in Some
        Ok(parsed_int) => Some(parsed_int),
        // If parsing fails (invalid input), return None
        Err(_) => None,
    }
}

fn main() {
    // Test cases
    let valid_hex_string = "BF3C"; // Valid hexadecimal string
    let invalid_hex_string = "IJKL"; // Invalid hexadecimal string

    // Test the hex_string_to_int function with a valid hexadecimal string
    match hex_string_to_int(valid_hex_string) {
        Some(parsed_int) => println!("Parsed integer: {}", parsed_int),
        None => println!("Invalid hexadecimal input"),
    }

    // Test the hex_string_to_int function with an invalid hexadecimal string
    match hex_string_to_int(invalid_hex_string) {
        Some(parsed_int) => println!("Parsed integer: {}", parsed_int),
        None => println!("Invalid hexadecimal input"),
    }
}

Output:

Parsed integer: 48956
Invalid hexadecimal input

Explanation:

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

The function "hex_string_to_int()" takes a hexadecimal string 'hex_string' as input and attempts to parse it into a 'u64' integer using the "from_str_radix()" function. If parsing succeeds, the parsed integer is returned wrapped in 'Some'. If parsing fails (due to invalid input), 'None' is returned. The "main()" function provides test cases for both valid and invalid hexadecimal strings to demonstrate the behavior of the "hex_string_to_int()" function.

Rust Code Editor:

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