book/redirects/mutability.md

% Mutability

There is a new edition of the book and this is an old link.

Variables are immutable only by default; we can make them mutable by adding mut in front of the variable name.

let mut x = 5;
println!("The value of x is: {x}");
x = 6;
println!("The value of x is: {x}");

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Here are the relevant sections in the new and old books:

• in the current edition: Ch 3.01 — Variables and Mutability
• In the first edition: Ch 3.11 — Mutability