Three Rules, Enforced at Compile Time

Ownership is why Rust ships in the Linux kernel, Windows, and Android Bluetooth without a GC. The borrow checker encodes rules that C leaves to discipline and sanitizers (see The Rust Book — What is Ownership?).

Each value has exactly one owner
Only one owner at a time
When the owner goes out of scope, drop runs

Moves, Copies, and Borrows

rust
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Move types (String, Vec, Box) transfer heap ownership
Copy types (i32, bool, and other trivial types) duplicate bits
Borrowing: many shared &T or one &mut T at a time (References and Borrowing)

In C there is no borrow checker: "move" is a convention (hand off a pointer and clear the old one), "copy" is assignment of scalar values, and "borrow" is passing a pointer without transferring free responsibility.

For This Exercise

Read a mode from stdin (move, copy, borrow, or all) and print the exact lines required by the tests. Prefer the Rust language selector for the idiomatic exercise; the C starter teaches the same ideas with pointers so both languages stay valid.

Implement ownership demos driven by stdin mode.

Modes (first token of stdin):

move — show a move (Rust: String move; C: pointer handoff)
copy — show a Copy-type duplicate (integers)
borrow — show non-owning access (Rust: &String; C: pointer without free)
all — run move, copy, borrow then print the final summary line

Exact output lines are fixed by the sample and hidden tests. Do not print extra text.

Success criteria:

Correct line-for-line stdout for every mode
Rust: use real moves/borrows (not .clone() unless needed)
C: free only the final owner of heap memory

Three Rules, Enforced at Compile Time

Each value has exactly one owner
Only one owner at a time
When the owner goes out of scope, drop runs

Moves, Copies, and Borrows

rust
Loading…

Move types (String, Vec, Box) transfer heap ownership
Copy types (i32, bool, and other trivial types) duplicate bits
Borrowing: many shared &T or one &mut T at a time (References and Borrowing)

For This Exercise

Implement ownership demos driven by stdin mode.

Modes (first token of stdin):

move — show a move (Rust: String move; C: pointer handoff)
copy — show a Copy-type duplicate (integers)
borrow — show non-owning access (Rust: &String; C: pointer without free)
all — run move, copy, borrow then print the final summary line

Exact output lines are fixed by the sample and hidden tests. Do not print extra text.

Success criteria:

Correct line-for-line stdout for every mode
Rust: use real moves/borrows (not .clone() unless needed)
C: free only the final owner of heap memory

Understanding Ownership

Topic Overview

Three Rules, Enforced at Compile Time

Moves, Copies, and Borrows

For This Exercise

Implementation Task

Progressive Hints

Resources

Learn by building

Understanding Ownership

Topic Overview

Three Rules, Enforced at Compile Time

Moves, Copies, and Borrows

For This Exercise

Implementation Task

Progressive Hints

Resources

Learn by building