c++primer练习3.20

源代码：

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

int main() {
	vector<int>vec;
	int n;
	cout << "请输入一组数字：" << endl;
	
	while (cin >> n) 
		vec.push_back(n);
	cout << "相邻两项的和依次是：" << endl;
		for (int i = 0;i <= vec.size() - 1;i++)
		{
			cout << vec[i] + vec[vec.size()-1-i] <<" "<< endl;

		}
	
	if (vec.size() % 2 != 0) {
		cout << vec[vec.size()/2];
	}
	
	
	return 0;
	
}