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4 years ago
## string literals
### Instructions
Create the following functions:
- `is_empty`, that returns true if a string is empty
- `is_ascii`, that returns true if all characters of a given string is in ASCII range
- `contains`, that returns true if the string contains a pattern given
- `split_at`, that divides a string in two returning a tuple
- `find', that returns the index if the first character of a given string that matches the pattern
> This exercise will test how many times the **heap is going to be allocated**!\
> So try your best to allocate the minimum data on the heap!
### Notions
- https://doc.rust-lang.org/1.22.0/book/first-edition/the-stack-and-the-heap.html
- https://doc.rust-lang.org/rust-by-example/primitives/literals.html
### 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 {
}
```
### 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
$
```