Rust by Example

3 Literals and operators

Integers 1, floats 1.2, characters 'a', strings "abc", booleans true and the unit type () can be expressed using literals.

Integers can, alternatively, be expressed using hexadecimal, octal or binary notation using either of these prefixes: 0x, 0o or 0b.

Underscores can be inserted in numeric literals to improve readability, e.g. 1_000 is the same as 1000, and 0.000_001 is the same as 0.000001.

We need to tell the compiler the type of the literals we use. For now, we'll use the u32 suffix to indicate that the literal is an unsigned 32-bit integer, and the i32 suffix to indicate that it's a signed 32-bit integer. We'll cover the type system in another chapter, and give more details about type annotating literals in their own section.

The operators available and their precedence are similar to other C-like languages.

#![feature(core)] fn main() { // Integer addition println!("1 + 2 = {}", 1u32 + 2); // Integer subtraction println!("1 - 2 = {}", 1i32 - 2); // TODO ^ Try changing `1i32` to `1u32` to see why the type is important // Short-circuiting boolean logic println!("true AND false is {}", true && false); println!("true OR false is {}", true || false); println!("NOT true is {}", !true); // Bitwise operations println!("0011 AND 0101 is {:04b}", 0b0011u32 & 0b0101); println!("0011 OR 0101 is {:04b}", 0b0011u32 | 0b0101); println!("0011 XOR 0101 is {:04b}", 0b0011u32 ^ 0b0101); println!("1 << 5 is {}", 1u32 << 5); println!("0x80 >> 2 is 0x{:x}", 0x80u32 >> 2); // Use underscores to improve readability! println!("One million is written as {}", 1_000_000u32); }