Utk yg mo Bantu2 Keuangan saya..monggo ke Bank Central Asia BCA 5520166779 a.n. Andreas Tparlaungan Manurung (Indonesia) For those who would like to help support my finances ..please feel free to send it to Bank Central Asia (BCA) account number 5520166779 under the name Andreas Tparlaungan Manurung (Indonesia)

RECURSIVE IN PROGRAMMING

Recursion in programming is a technique where a function calls itself to solve a problem by repeatedly reducing it into smaller versions of the same problem.

Basic Structure

FUNCTION recursiveFunction(input):

    IF stopping condition is TRUE:
        RETURN result

    ELSE:
        RETURN recursiveFunction(smaller input)

The two essential parts are:

1. Base Case → the condition that stops the recursion.
2. Recursive Case → the function calls itself with a smaller/simpler input.

Example: Factorial

Mathematically:

5! = 5 × 4 × 3 × 2 × 1 = 120

Recursive Java example:

int factorial(int n) {
    if (n <= 1) {
        return 1;              // Base case
    }

    return n * factorial(n - 1); // Recursive case
}

Execution:

factorial(5)
    ↓
5 × factorial(4)
        ↓
        4 × factorial(3)
                ↓
                3 × factorial(2)
                        ↓
                        2 × factorial(1)
                                ↓
                                1

Then the results return upward:

1
↑
2 × 1 = 2
↑
3 × 2 = 6
↑
4 × 6 = 24
↑
5 × 24 = 120

Recursion vs. Looping

Concept	Description
Looping / Iteration	Repeats a block using for, while, or do-while
Selection	Chooses between alternatives using if-else, switch
Recursion	A function repeatedly calls itself
Base Case	Stops recursion
Recursive Case	Continues recursion

A simple way to remember it:

Iteration repeats a process. Recursion repeats a function by having the function call itself.

If the base case is missing or never reached, the program can continue calling itself until a stack overflow occurs.