How to know calculate the execution time of an algorithm in c++?

Question

I want to test which data structure is the best by looking at the run-time performance of my algorithm, how do I do it?

For example I already have a hashmap<

Answer 1

If you really want to decide between data structures, you need to devise a test that at least approximates how you will use the structure. Some structures perform better for small amounts of data, some perform better for large amounts of data. Some perform better when you do a lot of reads, some perform better when you are doing a lot of inserts/writes. Some perform better with data that is almost all the same, and some perform better with data that is very distinct. Some algorithms perform better if you only do them once, others perform better if you do them a million times, because they have better locality of code, making cache hits more likely. What I mean to say is, good luck :)