44 lines
938 B
Markdown
44 lines
938 B
Markdown
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# Variables.
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# Definition.
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## Immutable.
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Use the `let` keyword to start declaration. Types are specified after the variable name.
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```rust
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let x: i32 = 10;
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```
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Type definition is optional, so you can drop it. I suggest specifying the type for global/class/etc variables, but dropping it in local scope like functions.
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```rust
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let x = "This is &str"; // Type is detected automatically: &str.
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```
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## Mutable.
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Add `mut` keyword after `let`.
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```rust
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let mut x: i32 = 10;
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x = 12;
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```
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## Constants.
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To declare constant, use the `const` keyword instead of `let`. Constant values always require type definition.
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```rust
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const NUMBER: i32 = 10;
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```
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# Shadowing.
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You can redefine a variable with the same name but with a different type. This is useful if you cast something, but want to keep the same variable name. To do this, just declare the variable again.
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```rust
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let x: &str = "&str"; // &str.
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let x: i32 = 10; // i32.
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```
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