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Update explanation of first_word function #4698

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6a1b4e2
Update explanation of first_word function
RustoMCSpit Mar 19, 2026
25f1466
Update ch04-03-slices.md
RustoMCSpit Mar 19, 2026
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11 changes: 7 additions & 4 deletions src/ch04-03-slices.md
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Expand Up @@ -106,7 +106,10 @@ values that were calculated from data in a particular state but aren’t tied to
that state at all. We have three unrelated variables floating around that need
to be kept in sync.

Luckily, Rust has a solution to this problem: string slices.
Instead of outputting a 'usize', which is not a reference to the value,
we should use a string slice which is a reference to the value. This prevents
issues around changing states as references will still point to a value
even if it is changed, whilst 'usize' can only hold on to its own value.

### String Slices

Expand Down Expand Up @@ -193,9 +196,9 @@ looking for the first occurrence of a space. When we find a space, we return a
string slice using the start of the string and the index of the space as the
starting and ending indices.

Now when we call `first_word`, we get back a single value that is tied to the
underlying data. The value is made up of a reference to the starting point of
the slice and the number of elements in the slice.
Now when we call `first_word`, by using '&str' instead of 'usize' we get
back a single value that is tied to the underlying data as it is a reference
to the starting point of the slice and the number of elements in the slice.

Returning a slice would also work for a `second_word` function:

Expand Down