$1.$ Write an example code that contains common sub expression $($Programme$-1).$

Rewrite the code to eliminate the common sub expression $($Programe$-2).$ Code both

these programmes in any programming language of your choice. Run this

programmes in your computer$/$laptop and measure the execution time, memory

usage and compare them.

$2.$ Briefly illustrate the process of using inference rules for type checking with

example.