#include <string>
#include <iostream>
#include "stdlib.h" // for atoi

using std::string;
using std::getline;

using std::cout;
using std::cin;
using std::endl;
using std::istream;
using std::streambuf;

int ClearError(istream& isIn)     // Clears istream object
{
  streambuf* sbpThis;
  char szTempBuf[20];
  int nCount, nRet = isIn.rdstate();

  if (nRet) {                     // Any errors?
    isIn.clear();                 // Clear error flags
    sbpThis = isIn.rdbuf();       // Get streambuf pointer
    nCount = sbpThis->in_avail(); // Number of characters in buffer

    while (nCount) {              // Extract them to szTempBuf
      if (nCount > 20) {
        sbpThis->sgetn(szTempBuf, 20);
        nCount -= 20;
      }
      else {
        sbpThis->sgetn(szTempBuf, nCount);
        nCount = 0;
      }
    }
  }
  return  nRet;
}

void main (void)
{
  int i;
  string s1("This is the first string");
  cout << s1 << endl << endl;

  s1 = "This is a test.";
  cout << s1 << endl << endl;

  s1.append("  What's up!");
  cout << s1 << endl << endl;

  for (i=0; i < s1.length(); i++)
    cout << s1[i];
  cout << endl;

  for (i=0; i < s1.length(); i++)
    cout << s1.at(i);
  cout << endl;

  s1.insert(5, "class ");
  cout << s1 << endl << endl;

  s1.erase(s1.find("W"));
  cout << s1 << endl << endl;

  int choice;

  while (choice != 5) {
    choice = 0;
    cout << "Please enter a choice (1-5; 5=quit): ";
    cin >> choice;
    ClearError(cin);
    if ((choice >= 1) && (choice < 5)) {
      cout << "Choice = " << choice << endl << endl;
    }
  }
  cout << "Done!" << endl << endl;
}