第八章

#include<iostream>
using namespace std;

int main()
{
    wchar_t w_ch;
    wcin.imbue(locale("chs"));
    wcout.imbue(locale("chs"));
    //设置语言环境
    wcin >> w_ch;
    wcout << w_ch << flush;
}
//io流对于unicode字符设计了wchar_t类型
//所以为什么不能用string

io对象无拷贝或者赋值，因此流不可能被设置为形参或返回类型。读写一个Io对象会改变流的状态，因而流不会是const的

int main()
{   
    //io流设置了四个状态位，good代表流是否有效，bad代表是否崩溃，fail代表是否有一个io操作失败，end表示是否流到达了文件结束。一个流一旦在某个地方发生错误，我们就不能用它读写数据。
    cout << "before read" << endl;
    if (cin.good()) cout << "cin's good" << endl;
    if (cin.bad()) cout << "cin's bad" << endl;
    if (cin.fail()) cout << "cin's fail" << endl;
    if (cin.eof()) cout << "cin's eof" << endl;

    read();
    cout << "after read" << endl;
    if (cin.good()) cout << "cin's good" << endl;
    if (cin.bad()) cout << "cin's bad" << endl;
    if (cin.fail()) cout << "cin's fail" << endl;
    if (cin.eof()) cout << "cin's eof" << endl;

    off();
    cout << "after off" << endl;
    if (cin.good()) cout << "cin's good" << endl;
    if (cin.bad()) cout << "cin's bad" << endl;
    if (cin.fail()) cout << "cin's fail" << endl;
    if (cin.eof()) cout << "cin's eof" << endl;
    return 0;
}