Rust development notes

use std::io;
use std::io::Write;

fn main() {
println!("testing string\n");
io::stdout().flush().unwrap();
}

// Variables are immutable
fn main() {
let x = 5;
println!("The value of x is: {x}");
}

// mut annotation allows mutability
fn main() {
let mut x = 5;
println!("The value of x is: {x}");
x = 6;
println!("The value of x is: {x}");
}

println!("{}", TWENTY_BUT_TWICE)
}

Intergers , floating-point numbers, booleans, characters

number without fractional components.

i8,u8,i16,u16,i32,u32, i64, u64,i128,u128, isize, usize

let f : bool = false // sets f as boolean type with value of false

can group multiple values into one type . 2 primitive compund types tuple and Array

general way of grouping a number of values with different types ; fixed length cant grow or get smaller once declared.

fn main() {
let temps: (u32, i8) = (20, -8);

println!("{:?}", temps)
}

collection of multiple values must be same type

// writing an array with type and amount of elements inside the array
fn main() {
let a: [u32; 3] = [5, 10, 12];

println!("{:?}", a)
}

// Accessing value of an array's index

// Need this library to write to
use std::io;

fn main() {
let a = [
"egg", "apple", "banana", "mango", "jalap", "coconut", " kimshi", "sake", "tacos",
"burritos",
];

println!("\n");
println!("list = {:?}", a);
println!("\n");

println!("What index's value do you want to see?, out of bounds index will error out");

let mut index = String::new();

// input number here
io::stdin()
.read_line(&mut index)
.expect("A whole number fool");

let index: usize = index.trim().parse().expect("not a nubmer");

let element = a[index];

println!("value : {element}");
}

// Adding to an array ; every element of an array must have the same type ;
// arrays in Rust have a fixed length.

// Need this library to write to
use std::io;

fn main() {
// other ways to write an array
// let a: [i32; 5] = ["jerry", "joe", "jack", "josephine", "joshelyn"];
// let a = [3; 5];
// make it read ["jerry", "joe", "jack", "josephine", "john"]
let mut a = ["jerry", "joe", "jack", "josephine", "joshelyn"];
println!("{:?}", a);

// user input
let mut number = String::new();
io::stdin()
.read_line(&mut number)
.expect("Failed to read line");

// place user input on array at last position
a[4] = &number;

println!("{:?}", a);
}

// Adding to an array ; every element of an array must have the same type ;
// arrays in Rust have a fixed length.

// Need this library to write to
// std = crate ; io = module ;
use std::io;

fn main() {
// other ways to write an array
// let a: [i32; 5] = ["jerry", "joe", "jack", "josephine", "joshelyn"];
// let a = [3; 5];
// make it read ["jerry", "joe", "jack", "josephine", "john"]
let mut a = ["jerry", "joe", "jack", "josephine", "joshelyn"];
println!("{:?}", a);

// user input
let mut empty_string = String::new();

// function
io::stdin()
.read_line(&mut empty_string)
.expect("Failed to read line");

// place user input on array at last position
// here the trim() removes spaces, whitespace characters like newlines and tabs.
a[4] = &empty_string.trim();

// https://doc.rust-lang.org/std/fmt/index.html
println!("{:?}", a);
}