Blocks and Scopes

Blocks

A block in Rust contains a sequence of expressions, enclosed by braces {}. Each block has a value and a type, which are those of the last expression of the block:

1. ```
   fn main() {
   ```
2. ```
       let z = 13;
   ```
3. ```
       let x = {
   ```
4. ```
           let y = 10;
   ```
5. ```
           println!("y: {y}");
   ```
6. ```
           z - y
   ```
7. ```
       };
   ```
8. ```
       println!("x: {x}");
   ```
9. ```
   }
   ```

If the last expression ends with ;, then the resulting value and type is ().

This slide and its sub-slides should take about 5 minutes.

• You can show how the value of the block changes by changing the last line in the block. For instance, adding/removing a semicolon or using a return.