Which list to use?

Question

C++ / C#

Good afternoon, I am writing a term paper in C. You need to read data from a document. The data has a format (index, x-coordinate, y-coordinate), but it is out of order. I do not know in advance the number of lines in the document
. I need some kind of list so that I can store these structures under indexes, and add them to the list at a specific place. Would a dynamic array work? If it does, then how to use it correctly in my case?
For example: I'm reading the first element from the document, its index is 15, so I want to add its structure to the 15th place in the array, the next index is 10 for example, and so on.

Answer 1

fit.