Divide by zero and no error? [duplicate]

You are going to have DivideByZeroException only in case of integer values:

int total = 3;
int numberOf = 0;

var tot = total / numberOf; // DivideByZeroException thrown 

If at least one argument is a floating point value (double in the question) you'll have FloatingPointType.PositiveInfinity as a result (double.PositiveInfinity in the context) and no exception

double total = 3.0;
int numberOf = 0;

var tot = total / numberOf; // tot is double, tot == double.PositiveInfinity

You may check like below

double total = 10.0;
double numberOf = 0.0;
var tot = total / numberOf;

// check for IsInfinity, IsPositiveInfinity,
// IsNegativeInfinity separately and take action appropriately if need be
if (double.IsInfinity(tot) || 
    double.IsPositiveInfinity(tot) || 
    double.IsNegativeInfinity(tot))
{
    ...
}