c++ - 数据错误，重试

Question

我在一本书中找到了这段代码片段:

int ival;
// read cin and test only for EOF; loop is executed even if there are other IO failures
while (cin >> ival, !cin.eof()) {
    if (cin.bad())         // input stream is corrupted; bail out
        throw runtime_error("IO stream corrupted");
    if (cin.fail()) {                        // bad input
        cerr<< "bad data, try again";        // warn the user
        cin.clear(istream::failbit);         // reset the stream
        istream::iostate cin_state = cin.rdstate();
        continue;                            // get next input
    }
    // ok to process ival
}

如果我在命令窗口中点击'f'，就会出现无数“坏数据，重试”，cin_state为0X02，等于badbit。 Failbit一直没有搞清楚，为什么？

Answer 1

问题是 f 永远不会从输入流中删除，所以 cin >> ival 不断尝试一遍又一遍地读取它。

你需要跳过它。参见，例如，How does istream::ignore( ) work?