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

You might consider graphing the data and deriving its (mathematical) function. Run a few trials with, say, 10, 100, 1000, 10000, and 100000 iterations. Using the number of iterations as your x variable and the resulting time as your y variable, plot a graph. From this you can determine the function which describes the performance of the code, using linear regression (also know as curve-fitting in software) - I use Graphical Analysis for this.

Repeat the trials with other data-structures/code and do the same graphic procedure, then compare your graphs and functions.

You can also use this data to determine the effective Big O time-complexity for each data structure.