240408 문자열을 정수로 바꾸기 ,평균 구하기

public int solution(String s) {
	int answer = 0;
	char temp = s.charAt(0);
	int startIndex = (temp == '-' || temp == '+') ? 1 : 0;

	for (int i = startIndex; i < s.length(); i++) {
		char ch = s.charAt(i);

		int digit = ch - '0';
		answer = answer * 10 + digit;
	}

	if (temp == '-')
		answer *= -1;

	return answer;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/12925

public double solution(int[] arr) {
	int length = arr.length;
	int sum = 0;
	for (int i : arr) {
		sum += i;
	}
	return (double) sum / length;
}

출처:https://school.programmers.co.kr/learn/courses/30/lessons/12944