notes.md

Notes

Variable ownership in parameter passing

• Without parameter borrowing (moves str's ownership to called function)

  let str = String::from("Hello");
  function(str);
  // str cannot be used in this scope from this line onwards

• With parameter borrowing, without mutability

  str can still be used in the scope it was declared in, but function() cannot change its value.

  let str = String::from("Hello");
  function(&str);
  // str can still be used in this scope, because function()
  returned the ownership of str to this scope after returning

• With parameter borrowing and mutability

  Makes str mutable, so its value can be changed in function.

  let mut str = String::from("Hello");
  function(&mut str);
  // str is now "Hello, world!"
  .
  .
  fn function(str: &mut String){
    str.push(", world!");
  }