BASIC, how lines were stored in memory?

Question

As I understand BASIC had line numbers because at the time you had to use a line editor to input your program. It allowed you to do something like this: 20 END 10 PRINT "HELLO WORLD" This program would print `"HELLO WORLD"`. My question is how did BASIC allow you to enter lines this way? How were they stored in memory? I suppose it was a map of line numbers and pointers to lines themselves which was updated every time you input a line. But this map would have to be sorted before running a `LIST`/`RUN` command. Is that so? If not then how exactly did BASIC store commands in the memory?

Answer 1

The interpreter probably stores the source code in records of the form:

line #

statement

into an array..

it then sorts them by line number so that they are executed in order by line #