Rust Division Error Handling: Pattern Matching Success and Failure Cases

Last update on June 07 2025 13:03:49 (UTC/GMT +8 hours)

Write a Rust program that handles the result of a division operation, using pattern matching to distinguish between success and failure.

Sample Solution:

Rust Code:

fn main() {
    // Define dividend and divisor
    let dividend = 10;
    let divisor = 0; // Change to 0 to simulate division by zero error

    // Perform the division operation
    let result = divide(dividend, divisor);

    // Match on the result to handle success and failure cases
    match result {
        // If division is successful, print the result
        Ok(value) => println!("Result of division: {}", value),
        // If division fails (division by zero), print an error message
        Err(error) => println!("Error: {}", error),
    }
}

// Define a function named 'divide' that performs division and returns a Result
fn divide(dividend: i32, divisor: i32) -> Result<i32, &'static str> {
    // Check if divisor is zero
    if divisor == 0 {
        // If divisor is zero, return an error
        Err("Division by zero is not allowed!")
    } else {
        // If divisor is non-zero, perform the division and return the result
        Ok(dividend / divisor)
    }
}

Output:

Error: Division by zero is not allowed!

Explanation:

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

fn main() { ... }: This is the entry point of the program.
let dividend = 10; and let divisor = 0;: These lines define the dividend and divisor variables for the division operation. Change the value of 'divisor' to 0 to simulate a division by zero error.
let result = divide(dividend, divisor);: This line calls the "divide()" function with 'dividend' and 'divisor' as arguments and stores the result in the 'result' variable.
match result { ... }: This is a match expression that matches on the 'result' to handle both success and failure cases.
Ok(value) => println!("Result of division: {}", value),: This arm of the match expression is executed if division is successful ('Ok'). It prints the result of the division.
Err(error) => println!("Error: {}", error),: This arm of the match expression is executed if division fails (division by zero) ('Err'). It prints an error message indicating division by zero.
fn divide(dividend: i32, divisor: i32) -> Result<i32, &'static str> { ... }: This function named divide takes two integers dividend and divisor as input and returns a Result. If the division succeeds, it returns Ok(result), where result is the quotient. If division by zero occurs, it returns Err("Division by zero is not allowed!").

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