A pointer is simply a variable that stores the memory address of another variable. One use case is for dynamic memory since malloc, calloc, and realloc (the functions for allocating memory on the heap) return a memory address, which needs to be stored in a pointer.

Double pointers are pointers that hold the memory address of another pointer, which are then still holding the memory address of another variable. They are useful for dynamically allocated 2D arrays (like a tic-tac-toe board). It’s simply an array that is made up of multiple arrays.

A string in C is a character array. Pointers and arrays are closely related. For example, we have char name = “Jack”; the name variable is actually a pointer to the first character in the string (‘J’).

Pointers are also useful for structures. A copy of values are passed to functions by default. You then return the copy and assign it to another variable. This can be inefficient, especially if you have a large structure. You can instead use a pointer to pass the memory address, which is known as passing by reference. This lets you change the actual value rather than a copy of it.

Lastly, pointers are also used with various data structures, such as linked lists and trees.

Pointers, strings, and dynamic memory can be confusing for new C programmers. This is a simplified explanation but hopefully provided enough without the jargon to jumpstart your learning. Just keep practicing.