下面代码实现了对两个数组表示的正整数的高精度加法（数组低位在前），则横线上应填写？
vector < int > add(vector < int > a, vector < int > b) {
vector < int > c;
int carry = 0;
for (int i = 0; i < a.size() || i < b.size(); i++) {
if (i < a.size()) carry += a[i];
if (i < b.size()) carry += b[i];
_______________________ //在此处填入代码
}
if (carry) c.push_back(carry);
return c;
}
