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32 lines
769 B
Markdown
32 lines
769 B
Markdown
# Variables
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- Are Immutable by default
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- can be inferred but sometimes needs explicit typing
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```rust
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let foo = 5;
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```
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- Need to add mut keyword to enable rewriting, generally avoid unless actually used
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```rust
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let mut bar = 6;
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```
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# SHADOWING
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#### Cannot have mutable shadows
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allows for reuse of namespace instead of spaces_str and spaces_num
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```rust
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let spaces = " _ _ ";
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let spaces = spaces.len();
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// will output 5 instead of " _ _ " beacuse that is how long it is
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// the shadow of spaces (first) wont be printed until the overshadow of spaces goes out of scope
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println!("{spaces}"); // output: 5
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```
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not allowed shadow
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```rust
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let mut spaces = " _ _ ";
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spaces = spaces.len();
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```
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cannot change type of variable once declared |