floating point numbers

[darkfish]

I know it'll print the 2nd one bcause of the imprecision of the floating point number representation. what is the change if I want to solve this problem, could somone explain it to me?
---
double x = 9.5 * 0.1;
double y = 0.95;
if (x = = y)
printf("They are equal\n");
else
printf("They ar not equal.\n");

---

[boxfish]

You could multiply them both by 100 and round them to the nearest integer, but what exactly is the problem you are trying to solve?

[vmpstr]

Normally, you would do something like:

#define EPSILON 1e-6
 
if(fabs(x - y) < EPSILON) printf("They are equal\n");
else printf("They are not equal\n");
 

[Ganon11]

Of course, you could make a simple function to do this:

const double EPSILON = 1e-6;
 
int fEquals(double x1, double x2) {
   return fabs(x1 - x2) < EPSILON;
}
 
// ...
 
double x = 9.5 * 0.1;
double y = 0.95;
if (fEquals(x, y))
   printf("They are equal\n");
else
   printf("They ar not equal.\n");

[JosAH]

Better use the relative difference.

kind regards,

Jos

[darkfish]

thank you everyone, I've a much clearer idea now.