OT - C++ question. Options

[Jeff Krieger]

Does anyone know how to modify this small program that I wrote in C++ so that for every cout statement there is a statement that writes the exact same information to the file accelfig.txt? I use this program to generate acceleration values and write them to accelfig.txt and then I read these acceleration values into another program that I wrote that numerically integrates these figures to calculate 0 to 60 mph and 1/4 mile times, speed at the end of the 1/4 mile, maximum hp, 60 mph to 0 braking distance etc. I use the free C++ compiler from http://www.bloodshed.net/dev/devcpp.html .


//CalcAccl1

#include < iostream.h >
#include < stdio.h >

// This program calculates 30 seconds worth of acceleration values, assumed
// to be in ft/s^2, and writes them to the file accelfig.txt.

main()
{ FILE *fp;

int counter;

double acceleration = 0, time = 0;

fp = fopen("accelfig.txt", "w");

for (counter = 0; counter <= 1600; counter++)
{
acceleration = time + 10;
fprintf(fp, "%20.10f\n", acceleration);
cout << "\nThe acceleration at " << time << " seconds is " << acceleration << '\n';
time = time + 0.0025;
}

for (counter = 1601; counter <= 4800; counter++)
{
acceleration = 14;
fprintf(fp, "%20.10f\n", acceleration);
cout << "\nThe acceleration at " << time << " seconds is " << acceleration << '\n';
time = time + 0.0025;
}

for (counter = 4801; counter <= 12000; counter++)
{
acceleration = 62 - 4*time;
fprintf(fp, "%20.10f\n", acceleration);
cout << "\nThe acceleration at " << time << " seconds is " << acceleration << '\n';
time = time + 0.0025;
}


fclose(fp);
}

[Jeff Krieger]

If you want to use ostream fiiles the same way you use cout, you have to do a few includes, and set the output stream up. Once set up, you use it just like cout, except it's heading to a file.

Or, if you want the mundane approach, you could always switch back to C. Oops, I see you have. :-)


#include
#include
#include

main()
{
   // open a file for outpout
   ofstream oFile("newoutput.txt", ios::out);

   // check to make sure it worked
   if ( !oFile ) { //open failed?
       cerr << "open failed" << endl;
       exit (-1);
   }

   // write something to it

   oFile << "The horsepower at " << "etc" << endl;

   return 0;
}

This worked on GCC last time I tried it. (does it look familar? :-)

love kim.

Andy's way is much easier - besides, I just wanted to be able to write the output to a text file so I could check for errors more easily.

This worked on GCC last time I tried it. (does it look familar? :-)

Are you Kim the lady mathematician? Hey, do you know why a negative ... ah forget it.