Vectors, HashMaps Casting If-Let, While-Let Result Enum in Rust

casting.rs

fn main() {
    // using the as keyword you can cast a type to another
    let f = 21.32424242_f32;
    let i = f as u8;
    let c = i as char;
    
    println!("{} {} {}", f, i , c);
}

hashmaps.rs

use std::collections::HashMap;

fn main() {
   let mut hm = HashMap::new();
   
   hm.insert("ket", 12);
   hm.insert("dv", 12);
   hm.remove("dv");
   
   for (k, v) in &hm {
       println!("{}, {}", k , v)
   }
   
   match hm.get("ket") {
       Some(&n) => println!("{}", n),
       _ => println!("no match")
   }
}

if-let.rs

fn main() {
    let s = Some('c');
    
    match s {
        Some(i) => println!("{}", i),
        _ => {}
    }
    
    if let Some(i) = s {
        println!("{}", i);
    } 
    
}

result-enum.rs

enum Result<T, E> {
    Ok(T),
    Err(E)
}

fn main() {
  let x = some(10);
  
  match x {
    Some(x) => if()
  }
}

vectors-enum.rs

#[derive(Debug)]
enum Example {
    Float(f64),
    Int(i32),
    Text(String)
}

fn main() {
    let r = vec![
        Example::Float(33.3),
        Example::Int(32),
        Example::Text(String::from("I love school"))
    ];
    
    println!("{:?}", r);
}

vectors.rs

fn main() {
    // You can define a vector using the vec! macro
    let x = vec![1, 2, 3, 4];
    
    // You can also use this to define a vector
    let mut v: Vec<i32> = Vec::new();
    
    v.push(32);
    v.push(12);
    v.push(1);
    
    for i in &v {
        println!("{}", i);
    }
    
    println!("{} , {}", v.len(), v.capacity());
}

while-let.rs

fn main() {
    let mut s = Some(0);
    
    while let Some(i) = s {
        if i > 19 {
            println!("Quit");
            s = None;
        } else {
            println!("{}", i);
            s = Some(i + 2);
        }
    } 
    
}