문제

#include <string>
#include <vector>
using namespace std;

string solution(string s) {
	string answer = "";
	int size = s.size();
	int i;

	for (i = 0; i < size; i++) {
		if (s[i] == ' ') answer += s[i];
		else {
			if (i == 0 || s[i - 1] == ' ') { // lower -> upper
				if ('a' <= s[i] && s[i] <= 'z') answer += (s[i] - 'a' + 'A');
				else answer += s[i];
			}
			else { // upper -> lower
				if ('A' <= s[i] && s[i] <= 'Z') answer += (s[i] - 'A' + 'a');
				else answer += s[i];
			}
		}
	}
	return answer;
}

string solution2(string s) {
	string answer = "";
	int size = s.size();
	int i;

	answer += toupper(s[0]);
	
	for (i = 1; i < size; i++) {
		s[i - 1] == ' ' ? answer += toupper(s[i]) : answer += tolower(s[i]);
	}
	return answer;
}