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| author | Carol (Nichols || Goulding) <carol.nichols@gmail.com> | 2015-09-22 22:20:04 -0400 |
|---|---|---|
| committer | Carol (Nichols || Goulding) <carol.nichols@gmail.com> | 2015-09-22 22:20:04 -0400 |
| commit | c859550e6ce35bf9923a930aecb80cc83c8f6dff (patch) | |
| tree | 3d77b6715cc62d027f44af963cb722272f90edd7 /move_semantics/move_semantics2.rs | |
| parent | c6b7f1ba254104ae13bd9d0b593b0184e9ded7db (diff) | |
Incorporate Move Semantics exercises from Felix's tutorial
:+1: :+1: :+1:
Connects to #6
Diffstat (limited to 'move_semantics/move_semantics2.rs')
| -rw-r--r-- | move_semantics/move_semantics2.rs | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/move_semantics/move_semantics2.rs b/move_semantics/move_semantics2.rs new file mode 100644 index 0000000..79c1c56 --- /dev/null +++ b/move_semantics/move_semantics2.rs @@ -0,0 +1,53 @@ +// Make me compile without changing line 9! Scroll down for hints :) + +pub fn main() { + let vec0 = Vec::new(); + + let mut vec1 = fill_vec(vec0); + + // Do not change the following line! + println!("{} has length {} content `{:?}`", "vec0", vec0.len(), vec0); + + vec1.push(88); + + println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1); + +} + +fn fill_vec(vec: Vec<i32>) -> Vec<i32> { + let mut vec = vec; + + vec.push(22); + vec.push(44); + vec.push(66); + + vec +} + + + + + + + + + + + + + + +// So `vec0` is being *moved* into the function `fill_vec` when we call it on +// line 6, which means it gets dropped at the end of `fill_vec`, which means we +// can't use `vec0` again on line 9 (or anywhere else in `main` after the +// `fill_vec` call for that matter). We could fix this in a few ways, try them +// all! +// 1. Make another, separate version of the data that's in `vec0` and pass that +// to `fill_vec` instead. +// 2. Make `fill_vec` borrow its argument instead of taking ownership of it, +// and then copy the data within the function in order to return an owned +// `Vec<i32>` +// 3. Make `fill_vec` *mutably* borrow its argument (which will need to be +// mutable), modify it directly, then not return anything. Then you can get rid +// of `vec1` entirely -- note that this will change what gets printed by the +// first `println!` |
