书中页数：P282 代码名称：clearIO.cc
#include <iostream> using std::cin; using std::cout; using std::endl; #include <sstream> using std::istringstream; #include <string> using std::string; void read() { // turns on both fail and bad bits cin.setstate(cin.badbit | cin.eofbit | cin.failbit); } void off() { // turns off failbit and badbit but all other bits unchanged cin.clear(cin.rdstate() & ~cin.failbit & ~cin.badbit); } int main() { 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; }