C++ 1157 단어공부 // transform(대/소문자)

 

#include<iostream>
#include <string>
#include <algorithm>

using namespace std;

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(NULL);

	string C;
	cin >> C;
	int max = 0;
	int cnt = 0;
	int target;
	int a[26] = { 0 };
	transform(C.begin(), C.end(), C.begin(), (int(*)(int))toupper);
	for (int i = 0; i < C.size(); i++) {
		a[C[i] - 'A']++;
	}

	for (int i = 0; i < 26; i++)
	{
		if (a[i] > max) {
			max = a[i];
			cnt = 0;
			target = i;
		}
		if (max == a[i])
			cnt++;
	}
	if (cnt > 1)
		cout << '?' << '\n';
	else
		cout << (char)(target + 'A');
}