56 lines
1.5 KiB
Rust
56 lines
1.5 KiB
Rust
// AsRef and AsMut allow for cheap reference-to-reference conversions.
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// Read more about them at https://doc.rust-lang.org/std/convert/trait.AsRef.html
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// and https://doc.rust-lang.org/std/convert/trait.AsMut.html, respectively.
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// Execute `rustlings hint as_ref_mut` or use the `hint` watch subcommand for a hint.
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// Obtain the number of bytes (not characters) in the given argument.
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fn byte_counter<T: AsRef<str>>(arg: T) -> usize {
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arg.as_ref().as_bytes().len()
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}
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// Obtain the number of characters (not bytes) in the given argument.
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fn char_counter<T: AsRef<str>>(arg: T) -> usize {
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arg.as_ref().chars().count()
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}
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// Squares a number using as_mut().
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fn num_sq<T: AsMut<u32>>(arg: &mut T) {
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*arg.as_mut() = *arg.as_mut() * *arg.as_mut();
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn different_counts() {
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let s = "Café au lait";
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assert_ne!(char_counter(s), byte_counter(s));
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}
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#[test]
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fn same_counts() {
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let s = "Cafe au lait";
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assert_eq!(char_counter(s), byte_counter(s));
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}
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#[test]
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fn different_counts_using_string() {
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let s = String::from("Café au lait");
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assert_ne!(char_counter(s.clone()), byte_counter(s));
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}
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#[test]
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fn same_counts_using_string() {
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let s = String::from("Cafe au lait");
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assert_eq!(char_counter(s.clone()), byte_counter(s));
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}
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#[test]
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fn mult_box() {
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let mut num: Box<u32> = Box::new(3);
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num_sq(&mut num);
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assert_eq!(*num, 9);
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}
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}
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