Open file in input mode to see whether it exists. - C++ File Stream

C++ examples for File Stream:File Operation

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Description

Open file in input mode to see whether it exists.

Demo Code

#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;
int main()/*from  ww w.  jav a 2s.  co  m*/
{
   ifstream inFile;
   ofstream outFile;
   inFile.open("prices.dat");  // attempt to open the file for input
   char response;
   if (!inFile.fail())  // if it doesn't fail, the file exists
   {
      cout << "A file by the name prices.dat exists.\n Do you want to continue and overwrite it\n with the new data (y or n): ";
      cin  >> response;
      if (tolower(response) == 'n')
      {
         cout << "The existing file will not be overwritten." << endl;
         exit(1);  //terminate program execution
      }
   }
   outFile.open("prices.dat"); // now open the file for writing
   if (inFile.fail())  // check for a successful open
   {
      cout << "\nThe file was not successfully opened" << endl;
      exit(1);
   }
   cout << "The file has been successfully opened for output." << endl;
   return 0;
}

Result


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