wc: Count Lines, Words, and Characters

🎯 The Unix wc ("word count") tool reports how many lines, words, and characters a file holds.

In Python you'd lean on the string methods:

def wc(text):
    return (
        len(text.splitlines()),   # lines
        len(text.split()),        # words
        len(text),                # characters
    )

This is the first tool in the unix-tools track.

Every tool here follows the same shape: a pure function does the counting/transforming, and in a real CLI a thin wrapper would feed it text from a file or stdin.

You implement and test just the pure function here; keeping the logic pure is what makes it testable, and exactly how you'd structure a real Rust CLI.

Iterators + `.count()` replace `len(...)`

Python builds a throwaway list just to measure it (len(text.split())). Rust counts lazily: string-splitting methods hand back an iterator, and .count() walks it to a total without ever allocating a Vec:

let n = "a-b-c-d".split('-').count();   // 4

You need three iterators here: one that yields lines, one that yields whitespace-separated words, and one that yields characters. They all live on str; the docs linked below will point you to the right method names. Call .count() on each.

One subtlety for the word count: the whitespace splitter you want skips empty chunks, so " a b " is two words, not a pile of empty strings, the same behavior as Python's argument-less str.split().

Returning a tuple

Rust tuples work like Python's: group a fixed number of values of possibly different types.

Here all three are usize (Rust's type for sizes and counts), so the return type is (usize, usize, usize):

fn wc(text: &str) -> (usize, usize, usize) {
    // ...
    (lines, words, chars)
}

Your Task

Implement wc(text: &str) -> (usize, usize, usize) returning (lines, words, chars):

lines: number of lines (use .lines())
words: number of whitespace-separated words
chars: number of characters

An empty string has zero of everything.

Example

assert_eq!(wc("hello world"), (1, 2, 11));
assert_eq!(wc("one two three\nfour five\n"), (2, 5, 24));
assert_eq!(wc(""), (0, 0, 0));

Rust Platform