What is Big O of a loop?

Question

I was reading about Big O notation. It stated,

The big O of a loop is the number of iterations of the loop into number of statement

Answer 1

O(n) is used to messure the loop agains a mathematical funciton (like n^2, n^m,..).

So if you have a loop like this

  for(int i = 0; i < n; i++) {
     // sumfin
  }

The best describing math function the loops takes is calculated with O(n) (where n is a number between 0..infinity)

If you have a loop like this

     for(int i =0 ; i< n*2; i++) {

     }

Means it will took O(n*2); math function = n*2

    for(int i = 0; i < n; i++) {
         for(int j = 0; j < n; j++) {

         }
    }

This loops takes O(n^2) time; math funciton = n^n This way you can calculate how long your loop need for n 10 or 100 or 1000

This way you can build graphs for loops and such.