fn main() {
// Using local inference, the compiler knows that `elem` has type u8
let elem = 5u8;
// Create an empty vector (a growable array)
let mut vec = Vec::new();
// At this point the compiler doesn't know the exact type of `vec`, it
// just knows that it's a vector of something (`Vec<_>`)
// Insert `elem` in the vector
vec.push(elem);
// Aha! Now the compiler knows that `vec` is a vector of `u8`s (`Vec<u8>`)
// TODO ^ Try commenting out the `vec.push(elem)` line
println!("{}", vec);
}