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+[[Rust]]
+[[To put data on the heap use a Box]]
+
+
+---
+Each function has a frame consisting of variables. Those frames live on the stack.
+
+A frame is **deallocated when the function returns**.
+
+If we assign a variable such as 
+```rust
+let a = [0; 1_000_000];
+let b = a;
+```
+
+the value of a is **copied** to b (thus we get two huge arrays). This is **expensive**. Think about what happens when we call a function.
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