How to idiomatically convert between u32 and usize?

Question

This code works and prints \"b\":

fn main() {
    let s = \"abc\";
    let ch = s.chars().nth(1).unwrap();
    println!(\"{}\", ch);
}

On t

Answer 1

The as operator works for all number types:

let ch = s.chars().nth(n as usize).unwrap();

Rust forces you to cast integers to make sure you're aware of signedness or overflows.

Integer constants can have a type suffix:

let n = 1u32;

However, note that negative constants, such as -1i32 is internally - 1i32.

Integer variables declared without an explicit type specification are shown as {integer} and will be properly inferred from one of the method calls.