recursion sample

recursion_sample.cpp

#include<iostream>
#include<cmath>

using namespace std;

#define ARRAY_LENGTH(array) (sizeof(array) / sizeof(array[0]))

/*
 * forループで配列内の最大値を返す
 */
int get_max_forloop(int numbers[], int size){
  int max_number = 0;
	for(int i=0; i<size; i++)
		max_number =  max_number < numbers[i] ? numbers[i] : max_number;
	return max_number;
}
/*
 * forループで配列内の整数の合計を返す
 */
int get_total_forloop(int numbers[], int size){
	int total = 0;
	for(int i=0; i<size; i++)
		total += numbers[i];
	return total;
}

/*
 * 再帰を用いて配列内の最大値を探す
 */
int get_max_recursive(int numbers[], int size){
	if(size == 0) return 0;
	int tmp_number = get_max_recursive(numbers, size-1);
	return tmp_number > numbers[size-1] ? tmp_number: numbers[size-1];
	
}
/*
 * 再帰を用いて配列内の整数の合計を返す
 */
int get_total_recursive(int numbers[], int size){
	if(size==0) return 0;
	return numbers[size-1] + get_total_recursive(numbers, size-1);
}

int main(){
	int numbers[] = {1, 2, 3, 4, 5, 6, 7, 8, 10, 9};
	
	cout<< "--------get_max-------" << endl;
	cout<< get_max_forloop(numbers, ARRAY_LENGTH(numbers) ) <<endl;
	cout<< get_max_recursive(numbers, ARRAY_LENGTH(numbers) ) <<endl;
	cout<< "--------get_total-------" << endl;
	cout<< get_total_forloop(numbers, ARRAY_LENGTH(numbers) ) <<endl;
	cout<< get_total_recursive(numbers, ARRAY_LENGTH(numbers) ) <<endl;
	return 0;
}