104 lines
3.2 KiB
Rust
104 lines
3.2 KiB
Rust
use std::error::Error;
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fn main() -> Result<(), Box<dyn Error>> {
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//// 000_println.rs
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println!("Printed text.");
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print!("No new line.");
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//// 010_add_distract_math_literal_operator.rs
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//https://doc.rust-lang.org/rust-by-example/primitives/literals.html
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println!("1 + 2 = {}", 1u32 + 2);
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println!("1 + 2 = {}", 32 + 2);
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println!("1 - 2 = {}", 1i32 - 2);
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//println!("1 - 2 = {}", 1u32 - 2); // panic because of overflow, program halts !!
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// Short-circuiting boolean logic
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println!("true AND false is {}", true && false);
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println!("true OR false is {}", true || false);
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println!("NOT true is {}", !true);
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// Bitwise operations
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println!("0011 AND 0101 is {:04b}", 0b0011u32 & 0b0101);
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println!("0011 OR 0101 is {:04b}", 0b0011u32 | 0b0101);
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println!("0011 XOR 0101 is {:04b}", 0b0011u32 ^ 0b0101);
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println!("1 << 5 is {}", 1u32 << 5);
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println!("0x80 >> 2 is 0x{:x}", 0x80u32 >> 2);
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// Use underscores to improve readability!
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println!("One million is written as {}", 1_000_000u32);
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reverse((1,true));
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tuplez();
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// HTTP example
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let body = reqwest::blocking::get("https://api.coindesk.com/v1/bpi/currentprice.json")?.text()?;
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println!("body = {:?}", body);
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Ok(())
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}
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//// 020_tuples.rs
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// https://doc.rust-lang.org/rust-by-example/primitives/tuples.html
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// Tuples can be used as function arguments and as return values
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fn reverse(pair: (i32, bool)) -> (bool, i32) {
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// `let` can be used to bind the members of a tuple to variables
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let (integer, boolean) = pair;
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(boolean, integer)
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}
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// The following struct is for the activity.
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#[derive(Debug)]
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struct Matrix(f32, f32, f32, f32);
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fn tuplez() {
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// ---------- //
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// A tuple with a bunch of different types
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let long_tuple = (1u8, 2u16, 3u32, 4u64,
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-1i8, -2i16, -3i32, -4i64,
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0.1f32, 0.2f64,
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'a', true);
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// Values can be extracted from the tuple using tuple indexing
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println!("long tuple first value: {}", long_tuple.0);
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println!("long tuple second value: {}", long_tuple.1);
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// ---------- //
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// Tuples can be tuple members
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let tuple_of_tuples = ((1u8, 2u16, 2u32), (4u64, -1i8), -2i16);
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// Tuples are printable
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println!("tuple of tuples: {:?}", tuple_of_tuples); // !! {:?} is useful also for debugging
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// But long Tuples cannot be printed !!
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// let too_long_tuple = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13);
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// println!("too long tuple: {:?}", too_long_tuple);
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// TODO ^ Uncomment the above 2 lines to see the compiler error
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let pair = (1, true);
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println!("pair is {:?}", pair);
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println!("the reversed pair is {:?}", reverse(pair));
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// To create one element tuples, the comma is required to tell them apart
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// from a literal surrounded by parentheses
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println!("one element tuple: {:?}", (5u32,));
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println!("just an integer: {:?}", (5u32));
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//tuples can be destructured to create bindings
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let tuple = (1, "hello", 4.5, true);
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let (a, b, c, d) = tuple;
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println!("{:?}, {:?}, {:?}, {:?}", a, b, c, d);
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let matrix = Matrix(1.1, 1.2, 2.1, 2.2);
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println!("{:?}", matrix);
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}
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