21 lines
447 B
Markdown
21 lines
447 B
Markdown
|
Constants
|
||
|
|
=========
|
||
|
|
|
||
|
|
{{#include ../links.md}}
|
||
|
|
|
||
|
|
Constants can be defined using the `const` keyword and are immutable.
|
||
|
|
|
||
|
|
Constants follow the same naming rules as [variables].
|
||
|
|
|
||
|
|
```rust
|
||
|
|
const x = 42;
|
||
|
|
print(x * 2); // prints 84
|
||
|
|
x = 123; // <- syntax error: cannot assign to constant
|
||
|
|
```
|
||
|
|
|
||
|
|
Constants must be assigned a _value_, not an expression.
|
||
|
|
|
||
|
|
```rust
|
||
|
|
const x = 40 + 2; // <- syntax error: cannot assign expression to constant
|
||
|
|
```
|