Everything you manipulate when you run a computer program, and the program itself, has to reside somewhere in your computer’s memory—on a disk, in its RAM circuits, in various levels of cache, or in a CPU’s or GPU’s registers. It is not something we necessarily think about when we write programs, but it is an obvious truth: if objects aren’t found somewhere, we cannot work with them. The reason we can get away with not worrying about memory is that our programming language handles most of the bookkeeping.
Consider the classical “Hello, world!” program:
#include <stdio.h>
int main(void) ...
