Question

I noticed in another post, someone had done something like:

double d = 3.1415; int i = Convert.ToInt32(Math.Floor(d)); 

Why did they use the convert function, rather than:

double d = 3.1415; int i = (int)d; 

which has an implicit floor and convert.

Also, more concerning, I noticed in some production code I was reading:

double d = 3.1415; float f = Convert.ToSingle(d); 

Is that the same as:

float f = (float)d; 

Are all those otherwise implicit conversions just in the Convert class for completeness, or do they serve a purpose? I can understand a need for .ToString(), but not the rest.

Answer 1

Casting to int is implicit truncation, not implicit flooring:

double d = -3.14; int i = (int)d; // i == -3 

I choose Math.Floor or Math.Round to make my intentions more explicit.