更正后的代码： #include<iostream> #include<string> #include<sstream> #include<vector> using namespace std; bool judge_ip(string ip) { int j = 0; istringstream iss(ip); string seg; while (getline(iss, seg, '.')) if (++j > 4 || seg.empty() || stoi(seg) > 255) return false; return j == 4; } bool is_private(string ip) { istringstream iss(ip); string seg; vector<int> v; while (getline(iss, seg, '.')) v.push_back(stoi(seg)); if (v[0] == 10) return true; if (v[0] == 172 && (v[1] >= 16 && v[1] <= 31)) return true; if (v[0] == 192 && v[1] == 168) return true; return false; } bool is_mask(string ip) { istringstream iss(ip); string seg; unsigned b = 0; while (getline(iss, seg, '.')) b = (b << 8) + stoi(seg); if (!b) return false; b = ~b + 1; if (b == 1) return false; if ((b & (b - 1)) == 0) return true; return false; } int main() { string input; int a = 0, b = 0, c = 0, d = 0, e = 0, err = 0, p = 0; while (cin >> input) { istringstream is(input); string add; vector<string> v; while (getline(is, add, '~')) v.push_back(add); int first = stoi(v[0].substr(0, v[0].find_first_of('.'))); if (first != 127 && (!judge_ip(v[1]) || !is_mask(v[1]))) err++; else { if (!judge_ip(v[0])) err++; else { if (is_private(v[0])) p++; if (first > 0 && first < 127) a++; else if (first > 127 && first < 192) b++; else if (first > 191 && first < 224) c++; else if (first > 223 && first < 240) d++; else if (first > 239 && first < 256) e++; } } } cout << a << " " << b << " " << c << " " << d << " " << e << " " << err << " " << p << endl; return 0; }</string></int></vector></sstream></string></iostream>