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4 years ago
## string literals
### Instructions
Create the following functions:
- `is_empty`: that returns `true` if the string is empty.
- `is_ascii`: that returns `true` if all characters are within the ASCII range.
- `contains`: that returns `true` if the string contains the given pattern.
- `split_at`: that divides a string in two returning a tuple.
- `find`: that returns the index of the first character of a given string that matches the pattern.
### Expected functions
```rust
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pub fn is_empty(v: &str) -> bool {
}
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pub fn is_ascii(v: &str) -> bool {
}
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pub fn contains(v: &str, pat: &str) -> bool {
}
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pub fn split_at(v: &str, index: usize) -> (&str, &str) {
}
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pub fn find(v: &str, pat: char) -> usize {
}
```
> Your heap allocations will be monitored to ensure that you do not make too many allocations, and that your allocations are reasonably sized.
### Usage
Here is a program to test your function
```rust
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use string_literals::*;
fn main() {
println!("{}", is_empty(""));
println!("{}", is_ascii("rust"));
println!("{}", contains("rust", "ru"));
println!("{:?}", split_at("rust", 2));
println!("{}", find("rust", 'u'));
}
```
And its output
```console
$ cargo run
true
true
true
("ru", "st")
1
$
```
### Notions
- [stack and heap](https://doc.rust-lang.org/1.22.0/book/first-edition/the-stack-and-the-heap.html)
- [Literals](https://doc.rust-lang.org/rust-by-example/primitives/literals.html)