MPH to Minutes and Seconds to run a mile

[nuubee]

Hi all,

Ok, I've just been trying to write a program that will convert MPH (miles per hour) into the number of minutes and seconds it takes that person to run one mile. This is what I have:

#include <iostream>
using namespace std;

int main()
{

  double  mph, count = 1;
  int mpm, seconds;

  cout << "\n";
  cout << "Program that converts MPH into minutes and seconds per mile." << endl;

  cout << "Please enter the MPH at which you were running: ";
  cin >> mph;
  cout << endl;

  mpm = mph / 60;

  do{
    mpm = mpm * 2;
    count = count + 1;
  }
  while (mpm < 1);

  seconds = mpm % 60;

  cout << "You are running 1 mile in " << count << " minutes and " << seconds << " seconds.";
  cout << endl;

  return 0;

}

The compiler doesnt like the '%' in my code. Is that because it has to be an integer value to follow it? Also not too sure if i've opted for the simplest method to solve the problem.

Thanks in advance!

[Ancient Dragon]

The mod operator doesn't work on doubles -- only integers. And why is mph a double? Your program isn't even using the fractional parts so you might as well make it an integer and that will solve the problem for you.

[nuubee]

Hi, thanks for the quick response. I have changed MPH to an int, only now, when I run the program, it doesn't run any further than prompting the user for MPH at the beginning...?!

[Freaky_Chris]

Wrong it does, pick a number >= 60 it will work fine. mpm is an integer, integer's ignore and decimal places, so and number small that 60 when divided by 60 would make mpm equal to 0, thus 0*2 = 0, so the program continues to loop multiplying 0 by 2 until it reaches a number greater than one, which it won't.

Chris

[nuubee]

Ah, that would explain it! If I were to make MPM a double though, then the '%' part would not work later in the program..?

So I would have to type cast it in some way?

[Ancient Dragon]

use fmod() function for doubles. Also do division with doubles, not integers or you will have problems with that too.