/*

  Some code illistrating how to put numerical output into a file
  suitable for Matlab.  See 
  
     http://www.math.nyu.edu/faculty/goodman/teaching/SciComp2003
  
  for more information.             
  
  This routine created a file called lis.m, which is a Matlab m-file,
  that contains all the data from the run.  To examine the data, start
  Matlab and type "lis", which will execute this file.   */
  

#include <math.h>     /* Declarations of the routines in the math library. */

#include <iostream.h> /* The C++ io library.  This makes "cin" and "cout"
                         possible.  */
                         
#include <fstream.h>  /* The C++ routines that communicate with files.  
                         These make "ifstream" and "ofstream" possible. */
                         
#include <iomanip.h>  /* So that we can format the output.              */

#define  N   1000 /* The size of the array for output.  */
#define AMAX 10  /* A bound on a.   */
#define TMAX 50  /* The maximum time for plotting */
#define OutputFileName "lis.m"    /* The name of the output file */

int main() {

   int k;
   float t, dt, x, y, a;
   
//  Get the input data from the user.
   
   cout << "Type a" << endl;
   
   cin >> a;
   
   if ( abs(a) > AMAX ) {
      cout << "Stopping because specified a = " << a 
           << " is bigger than AMAX = " << AMAX << endl;
      return 1; }
      
//  Open the ouput file and set up the parameters for output

   ofstream outFile;  // Declare the output file, an object of typo ofstream.
      
   outFile.open(OutputFileName, ios::out ); // Open the file.
   
      if ( ! outFile ) { //  If the file was not opened properly, bail out.
      
           cout << "In main program, outfile.open could not open file "
                << OutputFileName << ".  Stopping here and returning." << endl;
           return 2;
       }
       
/*  Set up the format so that floating point numbers are printed in a
    uniform way.  */ 
      
   outFile << setprecision( 7 );  
           // Print six digits after the decimal point.
           
   outFile.setf( ios::scientific, ios::floatfield );  
           //  Scientific notation with all zeros printed.
           
           
// Start the computation.

   // The first lines are Matlab commands that record parameters.
   // If N is 100, the first line will be: "N =   100;".  We often 
   // end Matlab commands with a semicolon.

   outFile << "N = " <<   N  << ";" << endl;
   outFile << "a = " <<   a  << ";" << endl;
   outFile << "T = " << TMAX << ";" << endl;
   outFile << "V = [ " << endl;    // The beginning of the output array.
   
   t = 0;
   dt = ( (float) TMAX)/ N ;
   
   for ( k=0; k < N; k++ ){
      x =   cos(t);
      y = cos(a*t);
      outFile << t << "  " << x << "  " << y << endl;
      t += dt;
     }
    
   outFile << " ] ; " << endl;
   
   return 0;
   
  }