#include <iostream>                              // For standard streams

int main()
{
    int a = -1;
    std::cin >> a;

    std::cout << "state-fail:"<<std::cin.fail() << std::endl;
    std::cout << "state-good:"<<std::cin.good() << std::endl;
    std::cout << "state-bad:"<<std::cin.bad() << std::endl;
    std::cout << "state-eof:"<<std::cin.eof() << std::endl;

    std::cin.clear();

    std::cout << " after std::cin.clear()" << std::endl;
    std::cout << "state-fail:"<<std::cin.fail() << std::endl;
    std::cout << "state-good:"<<std::cin.good() << std::endl;
    std::cout << "state-bad:"<<std::cin.bad() << std::endl;
    std::cout << "state-eof:"<<std::cin.eof() << std::endl;

    std::cout << "a = " << a << std::endl;

    std::cin >> a;//并没有执行！！！！！
    std::cout << "a = " << a << std::endl;

    return 0;
}


>> ./a.out
q
state-fail:1
state-good:0
state-bad:0
state-eof:0
after std::cin.clear()
state-fail:0
state-good:1
state-bad:0
state-eof:0
a = 0
a = 0

首先输入q，导致std::cin失效，但是我clear()以后，依然不可用，没有道理啊。
--
FROM 123.119.150.*