[c++] 파일 입출력

#include <iostream>
#include <fstream>
using namespace std;

int main() {
	ifstream fin("data.txt");
	ofstream fout("output.txt");

	int size, num, average = 0, sum = 0;
	if (fin.fail()) {
		cerr << "파일 열기 에러" << endl; return 1;
	}
	fin >> size;
	int* p = new int[size];

	for (int i = 0, *q = p; i < size; i++) {
		fin >> *q++;
	}

	for (int i = 0, *q = p; i < size; i++) {
		sum += *q++;
	}

	average = sum / size;


	if (fout.fail()) {
		cerr << "파일열기에러" << endl; return 1;
	}

	fout << "number of data: " << size << endl;
	fout << "sum: " << sum << endl;
	fout << "average: " << average << endl;


	return 0;
}