C++primer习题3.13

计算临界元素的和并输出
#include <iostream>
#include <vector>
using namespace std;

int main()
{
        vector<int> ivec;
        int i = 0;
        while(cin >> i)
                ivec.push_back(i);
        size_t len = ivec.size(), j = 0;
        for (; j != len-1; ++j)
        {
           cout << ivec[j]+ivec[j+1] << " ";
        }
        if ((j+1)%2)
        {
                cout << "The last num is not calculated his value"<<endl;
        }
}

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

int main()
{
        vector<int> ivec;
        int i = 0;
        while(cin >> i)
                ivec.push_back(i);
        size_t len = ivec.size(), j = 0;
        for (; j != len/2; ++j)
        {
           cout << ivec[j]+ivec[len-j-1] << " ";
        }
        if ((j+1)%2)
        {
                cout << "no match" << endl;
        }
}