2D Slice example in Rust.

main.rs

 std::fmt::Display;

type TwoDSlice<'a, T> = [&'a mut [T]];

fn print2dslice<T: Display>(two_d_slice: &Box<TwoDSlice<T>>) {
    for (row_idx, row) in two_d_slice.iter().enumerate() {
        println!("");
        for (col_idx, elt) in row.iter().enumerate() {
            print!("[{} {} {}] ", row_idx, col_idx, elt);
        }
    }
}

fn assignchar_2dslice<T: Display + From<u8>>(two_d_slice: &mut Box<TwoDSlice<T>>) {
    let mut i = 0;
    for row in two_d_slice.iter_mut() {
        for elt in row.iter_mut() {
            *elt = T::from('A' as u8 + i as u8);
            i = i + 1;
        }
    }
}

fn vector_to_slice<T>(mem: &mut Vec<T>, rows: usize, cols: usize) -> Option<Box<TwoDSlice<T>>> {
    if mem.len() < rows * cols {
        None
    } else {
        let mut slice = mem.as_mut_slice();
        let mut vec_rows = Vec::with_capacity(rows);
        for _i in 0..rows {
            let (row, rem) = slice.split_at_mut(cols);
            vec_rows.push(row);
            slice = rem;
        }
        Some(vec_rows.into_boxed_slice())
    }
}

fn main() {
    let mut mem = vec!['a'; 2 * 3];
    let mut two_d_slice = vector_to_slice(&mut mem, 2, 3).unwrap();
    println!("Initialized 2D Array");
    print2dslice(&two_d_slice);
    println!("\nRe-Assigning");
    assignchar_2dslice(&mut two_d_slice);
    print2dslice(&two_d_slice);
}