Verifying Time Complexity of Binary Search using Dafny

Formal software verification techniques are widely used to specify and prove the functional correctness of programs. However, nonfunctional properties such as time complexity usually carried out with pen paper. Inefficient code in terms may cause massive performance problems large-scale complex systems. We present a proof concept for using Dafny tool verify worst-case binary search. This approach can also be academic purposes new way teach algorithms complexity.