rust-by-practice/solutions/collections/String.md

fn main() {
    let mut s: String = String::from("hello, ");
    s.push_str("world");
    s.push('!');

    move_ownership(s.clone());

    assert_eq!(s, "hello, world!");

    println!("Success!")
}

fn move_ownership(s: String) {
    println!("ownership of \"{}\" is moved here!", s)
}

fn main() {
    let mut s: String = String::from("hello, ");
    s.push_str("world");
    s.push('!');

    borrow_string(&s);

    assert_eq!(s, "hello, world!");

    println!("Success!")
}

fn borrow_string(s: &str) {
    println!("ownership of \"{}\" is moved here!", s)
}

// FILL in the blanks
fn main() {  
   // get a slice of String with reference: String -> &str 
   let mut s = String::from("hello, world");

   let slice1: &str = &s; // in two ways
   assert_eq!(slice1, "hello, world");

   let slice2 = &s[0..5];
   assert_eq!(slice2, "hello");

   //Note! The type here cant be `&mut str` due to `push` is ONLY defined on String type and its mut reference: `&mut String` !
   // So you can't use `s.as_mut_str()`
   let slice3: &mut String = &mut s; 
   slice3.push('!');
   assert_eq!(slice3, "hello, world!");

   println!("Success!")
}

fn main() {  
   let mut s = String::from("hello, world");

   let slice1: &str = s.as_str(); 
   assert_eq!(slice1, "hello, world");

   let slice2 = &s[0..5];
   assert_eq!(slice2, "hello");

   //Note! The type here cant be `&mut str` due to `push` is ONLY defined on String type and its mut reference: `&mut String` !
   // So you can't use `s.as_mut_str()`
   let slice3: &mut String = &mut s; 
   slice3.push('!');
   assert_eq!(slice3, "hello, world!");

   println!("Success!")
}

fn main() {
    let s = String::from("hello, 世界");
    let slice1 = &s[0..1]; //modify this line to fix the error, tips: `h` only takes 1 byte in UTF8 format
    assert_eq!(slice1, "h");

    let slice2 = &s[7..10];//modify this line to fix the error, tips: `中`  takes 3 bytes in UTF8 format
    assert_eq!(slice2, "世");

    println!("Success!")
}

// FILL in the blanks
fn main() {
    let mut s = String::new();
    s.push_str("hello");

    // some bytes, in a vector
    let v = vec![104, 101, 108, 108, 111];

    // Turn a bytes vector into a String
    // We know these bytes are valid, so we'll use `unwrap()`.
    let s1 = String::from_utf8(v).unwrap();
    
    
    assert_eq!(s, s1);

    println!("Success!")
}