$ rustc OldMacDonaldLyrics.rs error[E0277]: the type `[&'static str]` cannot be indexed by `isize` --> OldMacDonaldLyrics.rs:14:63 | 14 | println!("and on that farm he had a {}, E-I-E-I-O,", animals[num]); | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[&'static str]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<&'static str>` to implement `Index<isize>` error[E0277]: the type `[&'static str]` cannot be indexed by `isize` --> OldMacDonaldLyrics.rs:15:32 | 15 | print!("with a {} {}", sounds[num], sounds[num]); | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[&'static str]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<&'static str>` to implement `Index<isize>` error[E0277]: the type `[&'static str]` cannot be indexed by `isize` --> OldMacDonaldLyrics.rs:15:45 | 15 | print!("with a {} {}", sounds[num], sounds[num]); | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[&'static str]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<&'static str>` to implement `Index<isize>` error[E0277]: the type `[&'static str]` cannot be indexed by `isize` --> OldMacDonaldLyrics.rs:16:46 | 16 | println!(" here and a {} {} there,", sounds[num], sounds[num]); | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[&'static str]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<&'static str>` to implement `Index<isize>` error[E0277]: the type `[&'static str]` cannot be indexed by `isize` --> OldMacDonaldLyrics.rs:16:59 | 16 | println!(" here and a {} {} there,", sounds[num], sounds[num]); | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[&'static str]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<&'static str>` to implement `Index<isize>` error[E0277]: the type `[&'static str]` cannot be indexed by `isize` --> OldMacDonaldLyrics.rs:17:44 | 17 | println!("here a {}, there a {},", sounds[num], sounds[num]); | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[&'static str]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<&'static str>` to implement `Index<isize>` error[E0277]: the type `[&'static str]` cannot be indexed by `isize` --> OldMacDonaldLyrics.rs:17:57 | 17 | println!("here a {}, there a {},", sounds[num], sounds[num]); | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[&'static str]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<&'static str>` to implement `Index<isize>` error[E0277]: the type `[&'static str]` cannot be indexed by `isize` --> OldMacDonaldLyrics.rs:18:40 | 18 | println!("everywhere a {} {}", sounds[num], sounds[num]); | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[&'static str]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<&'static str>` to implement `Index<isize>` error[E0277]: the type `[&'static str]` cannot be indexed by `isize` --> OldMacDonaldLyrics.rs:18:53 | 18 | println!("everywhere a {} {}", sounds[num], sounds[num]); | ^^^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[&'static str]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<&'static str>` to implement `Index<isize>` error[E0308]: mismatched types --> OldMacDonaldLyrics.rs:26:13 | 26 | while i < animals.len() { | - ^^^^^^^^^^^^^ expected `isize`, found `usize` | | | expected because this is `isize` | help: you can convert a `usize` to an `isize` and panic if the converted value doesn't fit | 26 | while i < animals.len().try_into().unwrap() { | ++++++++++++++++++++ error: aborting due to 10 previous errors Some errors have detailed explanations: E0277, E0308. For more information about an error, try `rustc --explain E0277`.