computer grammar recursion is good choice for searchenumerationand divide-and-conquer use recursion as alternative to deeply nested iteration loops for examplerecursion is much better when you have an undefined number of levelssuch as the ip address problem generalized to substrings if you are asked to remove recursion from programconsider mimicking call stack with the stack data structure recursion can be easily removed from tail-recursive program by using while-loop--no stack is needed (optimizing compilers do this if recursive function may end up being called with the same arguments more than oncecache the results--this is the idea behind dynamic programming (table top tips for recursion { { { { { { { figure the power set of { is {{ }{ }{ }{ }{ }{ }{ }as an examplelet { pick any elemente firstwe recursively compute all subsets of { to do thiswe select this leaves us with { now we pick and get to base case so the set of subsets of { is {union with { } {{}{ }the set of subsets of { then is {{}{ }union with {{ }{ }} {{}{ }{ }{ }the set of subsets of { then is {{}{ }{ }{ }union with {{ }{ }{ }{ }} {{}{ }{ }{ }{ }{ }{ }{ }}def generate_power_set input_set )generate all subsets whose intersection with input_set [ input_set to_be_selected is exactly selected_so_far def directed_power_set to_be_selected selected_so_far )if to_be_selected =leninput_set )power_set append (listselected_so_far )return directed_power_set to_be_selected selected_so_far generate all subsets that contain input_set to_be_selected directed_power_set to_be_selected