// This program uses the setprecision and fixed
// manipulators to format file output.
#include <iostream>
#include <iomanip>
#include <fstream>
using namespace std;

int main()
{
   fstream dataFile;
   double num = 17.816392;

   dataFile.open("numfile.txt", ios::out);   // Open in output mode

   dataFile << fixed;            // Format for fixed-point notation
   dataFile << num << endl;      // Write the number

   dataFile << setprecision(4);  // Format for 4 decimal places
   dataFile << num << endl;      // Write the number

   dataFile << setprecision(3);  // Format for 3 decimal places
   dataFile << num << endl;      // Write the number

   dataFile << setprecision(2);  // Format for 2 decimal places
   dataFile << num << endl;      // Write the number

   dataFile << setprecision(1);  // Format for 1 decimal place
   dataFile << num << endl;      // Write the number

   cout << "Done.\n";
   dataFile.close();             // Close the file
   return 0;
}