Need help ........

Ok I have written this program that will read in a list from another file then spit the file back out into a new one but listed. Now how can i sort this list by alpabetical order using the last name?

Code:

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#include <iostream.h>
#include <fstream.h>
#include <stdlib.h>

void main()
{
  ifstream inFile;
  ofstream outFile;
  char myInFile[] = "a:\\input.txt"; // The inout file.
  char myOutFile[] = "a:\\output.txt"; // The output file.

  inFile.open(myInFile);

  if(inFile){
    cout << "\nInput file " << myInFile << " was succesfully opened!!!!"
        << endl;
  } else {
    cout << "\nInput File " << myInFile << " could not be opened!!!!"
        << endl;
    exit(-1);
  }

  outFile.open(myOutFile);

  if(outFile){
    cout << "\nOutput file " << myOutFile << " was succesfully opened!!!!"
        << endl;
  } else {
    cout << "\nOutput File " << myOutFile << " could not be opened!!!!"
        << endl;
    exit(-1);
  }

  int account = 0;
  char fName[20];
  char lName[20];
  float amount = 0;
  char dummy;

  outFile << "This is the data that was read in." <<endl <<endl;

  inFile >> account >> fName >> lName >> amount; // Prime Read

  while(inFile){

    outFile << account << ' ' << fName << ' ' << lName
                    << ' ' << amount << endl;

    inFile >> account >> fName >> lName >> amount;

  } //while

  outFile << "\nThe end of the input!!!";
 
}

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