SOURCE FILE: myCat.cpp

/* The purpose of this program is to get the
   name of a text file from the user and
   print the file to standard output.  

   It was written to illustrate how to use
   strings, files and functions with a C++
   program. */

/* 'include statements' and 'using'
   directives that allow the program to use
   functions and variables that are in
   libraries. */

#include <fstream>
#include <iostream>
#include <string>
#include <assert.h>

using namespace std;

  /* function prototypes -- 
     to let the compiler know 
     the functions exist. */

string GetFileName () ;
void  PrintFile (string filename) ;

   /* The main function - every C++ program
      has exactly one main function.  This is
      where execution always begins. */

int main()
{       /* declare a variable of type 'string' */
   string filename ;   
        /* Call a function and capture the string returned */
   filename = GetFileName () ;
        /* Call a function to print the file */
   PrintFile (filename) ;  
   
   return 0 ;
}
 
/* Definition of the GetFileName function 

   The function heading indicates that this
   function returns a string and has no
   parameters. */
    
string GetFileName ()
{
   string file_name ;

      /* Output a prompt to the standard output stream */
   cout << "Please type the name of the file you would like to see: " ;

      /* Input the string the user enters from standard input */
   cin >> file_name ;

      /* Return file_name to the caller - and
	 halt execution of this function */
   return file_name ; 
}

/* Definition of the PrintFile function

   The 'void' keyword starting the function
   heading indicates that this function does
   not return a value.  The parameter list
   shows that it has a value-parameter of
   type string. */

void  PrintFile (string filename)  
{
       /* Output a blank line to standard output */
  cout << endl ;

    /* Declare a file variable 'inFile', bind
       it the file, and open the file. */

  ifstream inFile (filename.c_str()) ;

      /* Declare a variable of type char (character) */
  char nextChar ;

      /* We continue a loop while the
	 operation of getting the next
	 character from the file is
	 successful. */

  while (inFile.get(nextChar) )
  {
        /* We simply write each character we read.  
           We write to standard output. */
    cout << nextChar ;
  }
  
  cout << endl ;

      /* Close the file */
  inFile.close() ;
}