Can a near-zero floating value cause a divide-by-zero error?

Question

Everybody knows you\'re not supposed to compare floats directly, but rather using a tolerance:

float a,b;
float epsilon = 1e-6f;
bool equal = (fabs(a-b) < eps         


        

Answer 1

To answer the question in the title of your post, dividing by a very small number will not cause a division by zero, but it may cause the result to become an infinity:

double x = 1E-300;
cout << x << endl;
double y = 1E300;
cout << y << endl;
double z = y / x;
cout << z << endl;
cout << (z == std::numeric_limits::infinity()) << endl;

This produces the following output:

1e-300
1e+300
inf
1