Definition
Saperate big problem into small repeated parts and solve the problem.
All Recursion can be converted to Loop.
Good and bad points
| Loop | Recursion |
|---|---|
| intuitive | complicated |
| Long codes | short codes |
| good readability | bad readability |
| use less stack memories | use much stack memories |
| very low possiblity to get Stack overflow | Stack overflow if too mcuh call |
| very low possiblity to get overhead issue | overhead issue: call function repeatly will make program slow |
| each level of variable state will not saved | each level of variable state will saved because of stack |
Actual code
We should write recursion because it is good for reading and fixing it.
However, we need to use loop when..
- input may cause stack overflow : If the program need to calculate huge number of Fibonacci sequence
- the program need to be fast : call loop function 10 million times in 1 second.