Summary

Everything we use in our program must be stored in memory

The stack is the primary place where our values are stored

The stack cannot hold Dynamically Sized Types

Strings are Dynamically Sized Types, and therefore we store references to them on the stack

String literals are stored in program memory

References to string literals have a special reference lifetime, 'static

You can heap allocate memory for strings

The String struct wraps up a heap allocation in a type that can be stored on the stack

The String struct is also known as an owned string, while str is a string slice

You can use the + operator to combine owned strings

The long name for String is std::string::String, which you’ll sometimes see in error messages

Thanks to deref coercion, when you borrow a String, you can get either a &String or a &str

When you write functions, it’s better to use &str rather than &String as parameters so that your functions work on both owned strings and string literals

It’s typically best practice to store owned Strings in structs rather than references

You can use the format! macro to construct Strings

Owned Strings automatically handle freeing of memory, and prevent a lot of very common bugs