How to idiomatically convert between u32 and usize?

This code works and prints "b":

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

On the other hand, this code results in a mismatch type error.

fn main() {
    let s = "abc";
    let n: u32 = 1;
    let ch = s.chars().nth(n).unwrap();
    println!("{}", ch);
}

error[E0308]: mismatched types
--> src/main.rs:5:28
|
5 | let ch = s.chars().nth(n).unwrap();
| ^ expected usize, found u32


For some external reason, I have to use the u32 type for variable n. How can I convert u32 to usize and use it in nth()?

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.

Stack Overflow Q#43704758, score: 61