linear_search.rs

/**
 * Linear searching algorithm is a sequential searching algorithm, where we
 * traverse through each item by index and compare every element to the desired
 * element and return the index of the element.
 *
 * Example:
 *
 * Given array: [1, 5, 9, 2, 4], we want to search 9.
 *
 * step 1: check first item (index = 0), item = 1 , != 9
 * step 2: check second item (index = 1), item = 5 , != 9
 * step 3: check third item (index = 2), item = 9 , == 9 [return index : 2]
 **/

fn linear_search(array: &mut [i32], item: i32) -> Result<usize, i8> {
    for (index, _item) in array.iter().enumerate() {
        if _item.eq(&item) {
            return Ok(index);
        }
    }
    return Err(-1);
}
fn main() {
    let mut arr_1 = [1, 5, 9, 2, 8, 0, 10, 13, 7, 4, 6];
    let search_item = 10;
    let idx = linear_search(arr_1.as_mut(), search_item).unwrap();
    println!("The item {} is at index: {}", search_item, idx);
}

#[cfg(test)]
mod tests {
    use crate::linear_search;

    #[test]
    fn search_ok() {
        assert_eq!(linear_search([1, 4, 2, 5, 7].as_mut(), 5), Ok(3))
    }

    #[test]
    fn search_err() {
        assert_eq!(linear_search([1, 4, 2, 5, 7].as_mut(), 8), Err(-1))
    }
}