流条件状态练习

#include <iostream>
using namespace std;

int main()
{
    int ival;
    while(cin >> ival, !cin.eof())
    {
        if(cin.bad())
            throw runtime_error("IO stream corrupted");
        if(cin.fail())
        {
            cerr << "bad data, try again";
            cin.clear(istream::failbit);
            cin.setstate(istream::eofbit);//设置结束位结束while死循环
            continue;
        }
        cout << ival << endl;
    }
    return 0;
}

#include <iostream>

using namespace std;

istream & fun(istream &in)
{
    int ival;
    while(in >> ival, !in.eof())
    {
        if(in.bad())// input stream is corrupted; bail out, 流是否已被破坏
        {
            throw runtime_error("ERROE:IO stream corrupted");
        }
        if(in.fail())// bad input
        {
            cerr << "bad date, try again:";
            in.clear();
            in.setstate(istream::eofbit);// 结束死循环,如果去掉该句，当输入字符时候就会出现死循环
            continue;
        }
        cout << ival << endl;
    }
    in.clear();// 将in中的所有状态值都设为有效状态
    return in;
}

int main()
{
    cout << " Input some words ( ctrl + z to end ):
"; 
    fun(cin);
    return 0;
}