errorcheck.cpp

C++高级编程这本书所附的源代码

#include <iostream> 
#include <fstream> 
#include <string>

using namespace std; 

int main() 
{ 
  cout << "Enter numbers on separate lines to add. Use Control-D to finish (Control-Z in Windows)." << endl;
  int sum = 0; 

  if (!cin.good()) { 
    cout << "Standard input is in a bad state!" << endl; 
    exit(1); 
  } 

  int number;
  while (true) { 
    cin >> number;
    if (cin.good()) {
      sum += number; 
    } else if (cin.eof()) {
      break; // reached Reached end of file
    } else {
      // errorError!
      cin.clear(); // clear Clear the error state.
      string badToken;
      cin >> badToken; // consume Consume the bad input.
      cerr << "WARNING: Bad input encountered: " << badToken << endl;
    }
  } 

  cout << "The sum is " << sum << endl; 


  return 0; 
}