3、数组的中心位置

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

int main(){
	vector<int> vec;
	int num;

	while (cin >> num) {
		vec.emplace_back(num);
	}

	int i, rResult = 1;
	for (i = 1; i < vec.size(); ++i) {
		rResult *= vec[i];
	}

	int lResult = 1;
	if (rResult == lResult) {
		cout << "0" << endl;
		return 0;
	}

	for (i = 1; i < vec.size(); ++i) {
		lResult *= vec[i -1];
		rResult /= vec[i];
		if (rResult == lResult) {
			cout << i << endl;
			return 0;
		}
	}

	system("pause");
	return 0;
}