[30일코딩] Recursion

재귀, 귀납, 반복

Recursion

The process of defining a function or calculating a number

by the repeated application of algorithm. 

Same function within the function

- 함수 안에 함수 호출

- f(f(f(x))) 

- 러시아 인형처럼;

사용법

- Base Case & Recursive Case

- Same function within the function

public static int Summation(int x) {

// Base Case : At the End

if (x <= 0) {

return 0;

// additive identity property 

// Recursive Case : Keep Going

} else {

return x + Summation(x-1);

}

}

public static int exponentiation(int x, int y) {

// Base Case : At the End

if (y <= 0) {

return 1;

// multiplication identity property 

// Recursive Case : Keep Going

} else {

return x * exponentiation(x, y-1);

}

}