Moving code from Visual Basic to C++ issue - c++

Question

I'm facing an issue regarding the translation in C++ of a bunch of source code written in Visual Basic. In the code there is a call to the method Sign (VB) and various conversions of float to integer... Could you confirm that c++ code for 1, 2, 3 are the same as the VB one? In addition about the implicit conversion I've no idea how the conversion is performed (See 4). Any idea?
1) Method Sign (Visual Basic)
//C++
int sign(float value)
{
if (value < 0) return -1;
else if (value == 0) return 0;
else return 1;
}
2) Method Int (Visual Basic)
//C++
int Int(float value)
{
return ((value >= 0) ? value : floor(value));
}
3) Method CInt (Visual Basic)
//C++
int CInt(const float val)
{
float x = fabs(val - (int)val);
if (fabs(x - 0.5) < 0.0001)
return (int)val;
else
return (int)(val+(val>=0.0?0.5:-0.5));
}
4) And there is also an implicit conversion of double to int. How to make this conversion in c++?
//Visual basic
Dim dt As Integer = -99.2
Thanks you in advance,

Answer 1

1-
It is not the same, floating point values should not be compared to a constant variable (0, in this example). So, this is a better code for it:
const float epsilon = 0.00001f;
if(value < -epsilon) return -1;
if(value > epsilon) return 1;
return 0;
2- It depends on what you want for, for example -5.7. If you want -5, just cast away using (int). for example, if you have a float variable named f, use (int)f. If you want -6, use this function:
int Int(float value)
{
return ((value >= 0) ? (int)value : (int)(value-1));
}
3- It should work but last return statement could be made clearer:
return (int)val + (val>=0.0?1:-1)
4- Doubles are very very similar to floats in C/C++. Do as if you're messing with a float, not double.