c++ comparison not working... ! The code never stops executing

Asked Feb 04 '15 at 08:31

Active Feb 04 '15 at 08:32

Viewed 49 times

Why would this code not stop executing?? So when I execute this code, the value of x is 1.0 as a point but this won't stop executing. Please tell me why is this happening..!

#include <iostream>
#include <cmath>

using namespace std;


int main ()
{



  double x(0.0);
  double increment(0.1);

  //cout.setf(ios::fixed);
  while (x != 1.000000)
  {
    cout << x << endl;
    x += increment;

    if (x >= 1.1){
      break;
    }
  }

  return 0;


}

edited Feb 04 '15 at 08:32

Yu Hao

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asked Feb 04 '15 at 08:31

Shashank Agarwal

2

`x` will never be equal to `1.000000` because floating point numbers are not perfectly precise. – Maroun Feb 04 '15 at 08:32
http://stackoverflow.com/questions/17333/most-effective-way-for-float-and-double-comparison – Neska Feb 04 '15 at 08:33
I tried comparing x to 1.000000 and I even added cout.setf(ios::fixed); to the code, but it did not work! – Shashank Agarwal Feb 04 '15 at 08:33
in short: you need epsilon comparison. – Karoly Horvath Feb 04 '15 at 08:34
Or change `while (x != 1.000000)` to `while (x < 1.0)`. – Paul R Feb 04 '15 at 08:37
But I want to use (x != 1.0) or something like that ! – Shashank Agarwal Feb 04 '15 at 08:39
1

I tried your code, it's working pretty well after compiling with g++, even if I used 0.000001 as increment – youssef Feb 04 '15 at 08:47

c++ comparison not working... ! The code never stops executing

0 Answers0